Wilm's Tumor Power Notes [1]

What was Sidney Farber's contribution to the field of oncology?
Sidney Farber was the first to us adjuvant chemotherapy (Actinomycin D) to treat cancer (Wilm's tumor).

What syndromes is WT associated with and how often?
In 10% of cases, WT is associated with:
1. sporadic aniridia
2. isolated hemihypertrophy
3. Denys-Drash syndrome
4. genital anomalies
5. Beckwith-Wiedemann syndrome
6. WAGR (60% develop WT)

What are the main genes associated with WT, and what is the role of the protein produced by those genes?
WT1 and WT2 (reside on chromosome 11) are tumor suppressor genes that code for proteins that suppress growth inducing genes. Deletions in WT1 and WT2 predispose to WT.
WAGR is associated with WT1 and Beckwith-Wiedemann syndrome is associated with WT2

How often is WT bilateral in WAGR?
60% of patients with WAGR develop WT which is bilateral in 17% of cases

What is the relationship between Beckwith-Wiedemann syndrome and WT?
Kids with BW syndrome have a 40% chance of developing WT

How often is WT familial?
in up to 2% of cases

How does loss of heterozygosity (LOH) affect prognosis?
LOH (of chromosomes 1 or 16) is associated with increased risk of relapse and mortality.
LOH-16 present in 15-20% of WT, LOH-1 present in 10%

What is screening protocol for patient with syndromes associated with WT?
Ultrasound of kidneys every three months until the age of 5 YO

What are nephrogenic rests (NR) and what are their two distribution patterns?
NRs are persistent metanephric tissue beyond 36 weeks of gestation. The vase majority of NRs involute. They are found in two main distribution patterns.
1. Perilobular (PLNR): more common
2. Intralobular (ILNR)

What is the autopsy incidence of NRs?
~1%
PLNR: 0.9%
ILNR: 0.1%

What are the three histologic groups of NRs?
1. Incipient (infants)/Dormant (Older children): composed of blastemal and primitive epithelial cells that resemble embryonic kidney tissue and WT, but are microscopic and have sharp margins.
2. Regressing/Sclerosing (most common): show maturation of cellular elements. Progress to become obsolete rests composed of hyaline stromal elements (acellular proteinaceous material).
3. Hyperplastic: These are difficult to distinguish from WT, except based on architecture. They have uniform growth components that result in enlargement of the entire rest (preserving it's shape), as opposed to the neoplatic growth (WT) that results in a spherical expanding nodule within a rest.

How are hyperplastic NRs differentiated from WT?
The shape of the NR is preserved in hyperplastic NRs, and there is now surrounding pesudocapsule (which is found in WT). The importance of architectural characteristics makes a needle biopsy insufficient for differentiation unless they contain a part of the lesion's margin.

What is the association between WT and NRs?
41% of unilateral WT have NRs vs 99% of bilateral WT. NRs are increased in patients with WT associated with syndromes.

What is diffuse hyperplastic perilobar nephroblastomatosis (DHPLN) and what is it's radiologic characteristic?
DHPLN is an entity that can be confused with WT. Infants with DHPLN have unilateral or bilateral enlarged kidneys that maintain their their normal shape and lack necrosis. DHPLN can become WT (in ~50% of cases despite neoadjuvant chemotherapy) so they should be monitored closely. Changes in CT/MRI characteristics or evidence of growth of DHPLNs should raise concern for WT.

what is the treatment and prognosis of DHPLN?
Chemotherapy is used to decrease the size of DHPLNs, which may cause respiratory compromise by virtue of their size, but has not been shown to decrease the risk of malignant transformation. 100% transformation to WT in the absence of chemotherapy, vs 55% when biopsy/chemotherapy performed.
A high proportion of patients with DHPLN and WT will have anaplastic WT

Is nephrectomy justified in multicystic dysplastic kidneys?
No. Only 4% of these patients will have NRs and the risk of WT too low to justify prophylactic nephrectomies

What defines unfavorable histology WT (UH)?
Presence of focal or diffuse anaplasia. Anaplastic cells have large, pleomorphic, hyperchromatic nuecleii with abnormal mitotic figures. Focal anaplasia confers a better prognosis than diffuse anaplasia. Anaplasia is aassoicated more with respnse to therapy than tumor aggressiveness.

What are the two tumors that were considered WT UH and where split into a different category?
Clear cell sarcoma of the kidney (CCSK) and malignant rhabdoid tumors

What is the main difference between NWTSG and SIOP classifications?
NWTSG is a pre-treatment staging system while the SIOP assesses post treatment characteristics of the tumor.

What difference between Stage II and Stage III in terms of spillage?
Spillage is now considered Stage III regardless of whether it is local or diffuse, from a biopsy or tumor rupture. The extent of spillage affects the field of radiation given. Local spillage in the renal fossa is treated with local flank radiation; spillage outside the tumor bed mandates total abdominal radiation [2]

Is there a difference in terms of gross or microscopic post resection residual tumor in terms of staging?
No. Both are considered Stage III

How are tumors classified into risk groups based on neoadjuvant chemotherapy?
Based on histology at resection AFTER neo-adjuvant chemotherapy.
Low risk tumors are those that are completely necrotic (>99%)at time or resection
Blastemal predominant tumors (high risk) are those with more than 1/3 of tumor viable, and at least 2/3 of the viable tumor consists of blastemal cells.
Intermediate risk tumors are those with a variety of histologic charactaristics in between the low and the high risk categories.

What are the main pathologic characteristics of WT and how are they related to outcome?
WT is an embryonal neoplasm with blastemal, stromal, and epithelial components. Each of these can have variable levels of differentiation, including anaplasia.

What is particular about fetal rhabdomyomatous nephroblastoma and diffuse blastemal type WT?
Both these subtypes of WT. Fetal rhabdomyomatous nephroblastoma has poor response to chemotherapy, but excellent prognosis. Diffuse blastemal type has rapid response to chemotherapy, but characteristically presents with advanced disease

Which kids are at risk for anaplastic WT?
Kids older than 2 YO. Mortality from anaplastic WT ~ 60%. Outcome better for focal vs diffuse anaplasia.

What is the rate of metachronous contralateral disease and what are risk factors?
The rate of metachronous disease is 1% (synchornous is 5%). This is increased:
1. In the presence of NRs
2. Kids younger than two years
3. associated syndromes

What are the main characteristics of clear cell sarcoma of the kidney?
metastasis to bones and brain. Unclear cell origin

What are the main characteristics of malignant rhabdoid tumors of the kidney?
average age 11 months
characteristic involvement of perihilar renal parenchyma
second primary neurglial tumor in the brain

What are the main chemotheraputic agents used with WT?
Dactinomycin, vincristine, doxorubicin

When is doxorubicin added?
Stage III disease or in the presence of anaplasia

What are the aims of the main SWTS studies?
SWTS3: Use of Dox for Stage III dz
NWTS4: Dose intensification (less frequent) adequate with less hematologic toxicity
NWTS5: Effect of LOH on outcome in stage 1 and 2: decreased EFS
looked at management of relapse

What chemotheraputic agents are used for anaplasia?
Focal anaplasia: Vincristine/Dactinomycin/Doxorubicin
Diffue anaplasia: add cyclophosphamide +/- etoposide


What agents are used for CCSK and malignant rhabdoid tumors?
CCSK: Doxorubicin
Malignant rhabdoid: cyclophos/carbaplatin/etoposide (non of the basic WT agents)

What are the disadvantages of the routine use of neoadjuvant chemotherapy (SIOP)?
1. risk of losing staging information
2. risk of treating benign disease
3. modification of tumor histology by chemotherapy
4. Clear cell/rhabdoid will not respong
up to 10% rate of benign or altered malignant diagnosis in kids with pre-nephrectomy diagnosis of WT

What are the complications of doxorubicin?
1. cardiomyopathy in 1.2%
2. secondary malignancies (AML) in 1.6%

What are risk factors for a secondary malignancy?
1. doxorubicin
2. irradiation
3. prior treatment for relapsed tumor

What are the current guidelines for radiation therapy to lungs?
low dose radiation if lunges involved.

What is the significance of CT only lung lesions? [3]
Up to a third of lung lesions found on CT in patients with WT are not malignant.
Patients who are stage I or II FH WT should undergo biopsy of CT only lesions to gauge therapy. Those who are FH stage III or IV who are on AREN0533 protocol trial receive chemotherapy and then are reevaluated after 6 weeks. At that time, any residual lesions will get radiation, preferably after biopsy

What are guidelines for abdominal irradiation? [2]
Local Stage III disease. 10cGy


What are the main things that need to be assessed on imaging?
1. contralateral kidney involvement
2. two functioning kidneys
3. vascular involvement

What is the incidence of synchronous contralateral lesions?
5%

Is there a need for contralateral exploration and why?
No. Although 10% of lesions on the other side may be missed by imaging, these lesions do not affect outcome and recurrence, especially that some are NRs and not WT.

What are the false positive and false negative rates of clinical assessment of LN involvement?
The false positive rate of clinical assessment is ~20% and a false negative rate is 30%. Thus routine sampling of LN's (even when not suspicious) is mandatory for proper staging.

Why is cystoscopy important in the presence of hematuria?
Cystoscopy is important to rule out tumor extension into the bladder, where cutting through the ureter would result in cutting through the tumor, thus upstaging the patient.

What are factors related to increased risk of tumor recurrence?
Stage III
Intraoperative rupture
Anaplasia

What are indications for neoadjuvant chemotherapy (NWTSG)?[2]
1. solitary kidney
2. bilateral tumors: all bilateral tumors are treated with upfront chemotherapy. Any attempts at partial nephrectomy should be with held until week 6 or 12 [2]
3. horseshoe kidney
4. unresectable tumor
a.intravascular extension of tumor thrombus above hepatic veins
b.involvement of contiguous structures that would need to be sacrificed
c.if resection risks unnecessary morbidity and mortality per surgeon judgement
d.pulmonary compromise due to extensive pulmonary metastasis
5. respiratory distress form mass

Should both kidneys be biopsied in bilateral WT? [2]
No. Initially, and because of the risk of discordant pathology between the two kidneys, it was recommended that both kidneys be biopsied.
Per new COG protocol, renal biopsy is not necessary in stage V disease. Protocol calls for upfront 3 drub chemotherapy followed by possible OPEN biopsy (<50% reduction in size which may suggest presence of anaplastic tumor) or resection (tumor rendered resectable) or continued chemotherapy and resection at 12 weeks When is a core needle biopsy vs an open biopsy acceptable?
A core needle biopsy is acceptable to obtain a tissue diagnosis when a suspected WT tumor is deemed unresectable. An open biopsy is mandatory in the setting of bilateral WT that does not decrease in size by more than 50% after 6 weeks of chemotherapy.

How often is intravascular extension identified?
The renal vein is involved in 11% of children, the vena cava in 5% [2]. The Renal vein and VC should be palpated for the presence of tumor intraoperatively, even when preoperative imaging studies are normal.

Which patients are candidates for resection alone without adjuvant chemotherapy?
patients who are younger than two years, stage I, and <550 grams. LN's MUST be sampled and found negative for children to qualify. If LN's are not sampled, the child does not qualify for the surgery only protocol [2]
90% 4 year disease free survival

References: Ashcraft unless otherwise specified
1. Ashcraft's Pedatric Surgery. 5th edition. Chapter 67: Renal Tumors
2. COG renal biology protocol handbook. Accessed July 2011. Available at http://www.childrensoncologygroup.org/_files/disc/Surgery/RenalTumorsHandbook.pdf
3. Ehlrich et al. The value of surgery in directing therapy for patients with Wilm's tumor with pulmonary disease. A report from the National Wilm's Tumor Study Group (NWTS-5). Journal of Pediatric Surgery (2006);41:162-167

How often are common bile duct stones found in children suspected of having them?

This read stemmed from a literature search looking for articles addressing missed CBD stones in children not suspected of having them (no hx of jaundice, pancreatitis, normal CBD on U/S etc..). Instead I ran into this interesting article, out of Sick Kids in Toronto, looking at kids with findings consistent with CBD stones who were either managed by pre-operative ERCP, or had undergone an intra-operative cholangiogram, followed by ERCP when the IOC was positive.

202 patients with gallbladder stones, 48 of whom (23.7%) had suspected CBD stones. Preoperative ERCP, which was performed on a third of patients with suspected CBD stones, was positive in 21.4% of cases. Most of the rest of patients with suspected CBD stones underwent an IOC, which was positive in 6.5% of cases. Based on their results, the authors recommended an IOC as the initial investigative study since it involves less risk to the patient than does an ERCP, which was negative in around 80% of cases.

An IOC seems to be an excellent way to avoid unnecessary ERCP's, as long as a skilled gastroenterologist with a high ERCP success rate is available (to avoid a situation where a CBD stones are identified intraop, and an attempt at ERCP fails post op!). What is interesting about this study is the discrepancy between the finding of stones in the preoperative ERCP group and the IOC group. This could be because the ERCP may be more sensitive than the IOC, but potentially there might have been a selection bias, where patients who were more likely to have CBD stones (elevated bilirubin (8 vs 2), markedly dilated CBD (14 vs. 7) etc...) might have been selected to undergo and ERCP vs IOC.

Reference
Mah et al. Management of suspected CBD stones in children: role of selective IOC and ERCP. Journal of pediatric surgery (2004)39 :808-812

How can laparoscopy help evaluate patients with suspected rotational anomalies?

Again, the subject of rotational anomalies and equivocal UGI findings came up. The next day, this paper by Hsiao et al out of Sick Kids in Tornoto was in JPS. Here the authors discuss the utility of diagnostic laparoscopy as a tool to help corroborate UGI findings, or as a tie breaker for equivocal UGI studies.

The article was based on two premises. The first is what defines malrotation vs. non-rotation. Malrotation, here, was defines as the DJJ and the cecum near the midline, and the base of the mesentery less than 50% of the diameter of the abdomen. Non-rotation was defined as DJJ to the right of midline, ceceum in the lower left or central abdomen, small bowel on the left side, colon on the right, and base of mesentery is longer than 50% of the diameter of the abdomen. The other premise is that the small bowel is not at risk of midgut volvulus when the base of the mesentery is longer than 50% of the diameter of the abdomen (as in normal and non-rotation), and a Ladd's procedure is not necessary.

Very few people would argue that an infant with bilious emesis who is found to have an abnormal UGI needs exploration. The issue becomes more controversial when abnormal UGI studies are found in children with no symptoms or chronic and/or non-specific symptoms. This is the group of patients this paper addressed.

The UGI results studies included findings consistent with malrotation, malrotation with volvulus, non-rotation, or equivocal findings. Of the patients with UGI findings consistent with malrotation, ~60% had malrotation confirmed by laparoscopy (with or without volvulus), and the rest had either non-rotation (30%) or were normal (10%) (both conditions the authors believe do not need surgical correction). When UGI's showed non-rotation, laparoscopic evaluation was consistent with the diagnosis in all patients. Finally, of the patients with an equivocal UGI, a third had malrotation with/without volvulus, and the rest were found to be either non-rotated (48%) or normal (21%) on laparoscopic evaluation.

So if we accept that a mesenteric base longer than 50% of the diameter of the abdomen constitutes a stable mesenteric base not prone to volvulus (a finding confirmed by laparoscopy), laparoscopy can be an important tool that can help us manage this perplexing population of patients with no/vague symptoms and inconclusive UGI studies.


Reference:
Hsiaoo M, Langer JC. Value of laparoscopy in children with a suspected rotation abnormality on imaging. Journal of Pediatric Surgery (2011) 46, 1347-1352

Swimming with Sharks

Tumor spillage and Wilm's tumor: types and implications

Tumor spillage during resection of a Wilm's tumor has substantial implications on prognosis and therapy. Spillage immediately upstages a patient to Stage III, and depending on the type of spillage, commits the patient to either flank (local spillage) or total abdominal radiation (diffuse spillage).

Intraoperative recognition and documentation of spillage, whether pre-exiting or secondary to manipulation, thus has substantial implications on adjuvant therapy. With that in mind, it is important understand the different types of spillage or peritoneal soilage by tumor.

Based on the COG's AREN03B2 Renal Biology Protocol handbook (2010), the peritoneum is concidered soiled (tumor spill) when:

1. There is intraoperative tumor spillage
2. The tumor is biopsied
3. The tumor has ruptured

Spillage occurs whenever the tumor capsule is violated. If adherent organs (eg. diaphragm) are resected without violation of the capsule, this is not considered spillage. Whenever one cuts across tumor, including tumor present within vessels, or the tumor is removed in more than one piece, spillage is assumed to have occurred.

Tumor biopsy, whether done through a percutaneous anterior or retroperitoneal approach, or using an open approach, is considered local spillage unless indicated otherwise by the surgeon.

Tumor rupture can be spontaneous or post-traumatic with subsequent tumor cell dissemination in the peritoneal cavity. Tumor rupture is usually considered diffuse soilage, though in some cases it may be clearly isolated to the retroperitoneal space and considered local spillage. The presence of a hematoma implies tumor cell spread and diffuse soilage.

Because of the various types of soilage, and their different implications (either flank or total abdominal radiation), the surgeon should completely and clearly document how the soilage occurred and whether it was thought to be diffuse or local. If tumor thrombus is encountered, the surgeon must clearly describe whether it was removed en bloc, in more than one piece, and if residual thrombus was thought to be left behind.

Neuroblastoma Power Notes [1]

Where do neuroblastic tumors (NBT) arise from?
They arise from the sympathetic cells of the neural crest. Thus NB can occur in sympathetic ganglia, sympathetic para-ganglia, or adrenal gland.

How is NB differentiated from other small round blue cell tumors?
The histopathologic findings characteristic of NB are:
1. Rosettes: NB cells surrounding neural fibrils
2. Neuropil: neuritic processes
3. Schwannian cell stroma: reactive/non-neoplastic tissue, recruited by tumor cells, and composed mostly of sheets of spindle cells. Schwannian stroma has an antineoplastic/anti-angiogenic/pro-differentiating effect on NB cells. The amount of stroma present is the major factor that divides neuroblastic tumors into NB vs. ganglioneuroblastoma and ganglioneurooma. More Shwannian stroma imparts better prognosis

What is the Shimada classification and what is it based on?
The Shimada classification is an age-linked histopathologic classification that is used to divide neuroblastic tumors in to favorable and unfavorable histology groups. It depends on
1. Degree of cellular differentiation
2. Mitotic-Karyorrhectic index: Number of cells in mitosis or Karyorrhexis (cell death) per 5000 cells. MKI can be low (<100), intermediate (100-200), or high (>200).
3. age
4. Amount of Shwannian stroma
The Shimada classification has independent prognostic value, where FH tumors have a 90% 5 year EFS, and UH tumors have a 30% 5 year EVS.

How is the International Neuroblastoma Pathologic Classification (INPC) different from the Shimada classification?
The INPC is based on the Shimada classification. It divides neuroblastic tumors into 4 tumor categories under 2 distinct prognostic groups: favorable subgroup (FS) and unfavorable subgroup (US).
FS:
Ganglioneuroma differentiating
Ganglioneuroblastoma intermixed type
Ganglioneuroblastoma nodular (with specific favorable features)
US:
Ganglioneuroblastoma nodular (unfavorable features)
Neuroblastoma

What is the histopathologic definition of NB?
NB is a Shwannian poor neuroblastic tumor (<50% Schwannian stroma) divided into three main types 1. Undifferentiated: No neuropil present 2. Poorly differentiated: <5% cells showing signs of differentiation into ganglion cells and neuropil present 3. Differentiating: >5% cells showing signs of differentiation and neuropil present

What defines Ganglioneuroblastoma (GNB) and Ganglioneuroma (GN)?
GNB and GN are both Schwannian stroma rich neuroblastic tumors (>50%)

What are the characteristics of GNB?
GNB cells are progressing into mature ganglion cells with >50% of cells in the maturing form (not completely mature, otherwise would be ganglioneuroma). GNB has residual foci (vs scattered) of neuroblastic cells that constitute <50% of cells. GNB is divided into the intermixed type (GNB-I) (where the foci of neuroblastic cells are microscopic) and the nodular type (GNB-N) (where foci are macroscopic) The GNB-I type are considered under the favorable subgroup while the GNB-N can be either favorable or unfavorable subgroup based on INPC factors [2] What are the characteristics of GN?
GN divided into GN mature (composed of mature cells and no neuroblastic elements) and GN maturing. The GN-maturing contains scattered (vs. foci) differentiating neuroblastic cells. Unlike GNB, these cells do not form distinct foci.

What is Horner's syndrome?
Horners syndrome results from loss of sympathetic innervation to part of the face. It consists of:
1. Ptosis: drooping of the eyelid due to loss off innervation of the upper tarsal muscle
2. Mioisis: small pupil
3. Anhydrosis: Decreased sweating on the affected side of the face
4. Enphthalmos: Impression that the eye is sunken
5. Heterochromia (in children): due to decreased melanin pigment deposition in the pupil on the effected side, secondary to loss of sympathetic innervation

What is acute cerebellar ataxis?
Also referred to as the 'dancing eyes syndrome', usually occurs in infants with mediastinal masses and results from excessive catecholamine production
It consists of:
1. Myoclonus: brief, involuntary twitching of muscles
2. Opsoclonus: uncontrolled eye movement
3. Nystagmus

Where are NB's usually found?
Adrenal gland (50%), Paraspinal ganglia (25%), Thorax (20%), pelvis (4%), and neck (1%)

Where does NB metastasize to?
40% of NB are stage 4 (metastatic) at time of diagnosis. Metastasis is most frequently to bone (bone pain), Bone marrow (anemia), and lymph nodes.
Raccoon eyes result from retrobulbar venous plexus spread.

What is stage 4S NB?
A specific type of metastatic NB found in infants (<1 year). Primary tumor is localized (stage 1, 2A, or 2B) and spread is limited to: 1. Skin: blueberry muffin lesions 2. Liver: can cause respiratory distress from hepatomegaly 3. Bone marrow: malignant cells should be limited to <10% nucleated cells. Can cause anemia. What are the different options for diagnosis of NB?
1. Histopathology of primary tumor OR
2. Tumor cells in bone marrow + elevated urine catecholamines

What laboratory values correlate with NB tumor burden?
1. LDH
2. Catecholamines
3. Neuron specific enolase
4. Ferritin

How often are calcifications found on CT scan?
85% of cases

In what setting is MRI better than CT scan for NB imaging?
1. evaluation of stage 4 disease: Bone and bone marrow metastatic disease
2. evaluation of encroachment into neural foramen
3. evaluation of vessel encasement

What is MIBG scan and how does it work?
MethIodoBenzylGuanine is taken up by the storage granules in chromaffin cells, in the same way catecholamines are. Detects the primary tumor, involved LN's, and metastatic disease.

What is the main drawback of INSS and how is that counteracted?
The main drawback is the the staging and thus the prognosis is dependent on extent of resection, and thus the skill and aggressiveness of the surgeon. Image defined risk factors, those that preoperatively predict worse prognosis, can help provide a more uniform system for staging disease at presentation.Such factors include vessel encasement, extension into neural foramena etc...

What are the two main categories of determinants of prognosis?
1. Clinical factors: age and stage
2. Biological factors: NMYC, DNA plyody (in infants), histopathologic classification (Shimada)
additional variables include LOH: 1p or 11q deletions. Loss of tumor suppressor genes. Used to define duration of chemotherapy in some situations.

What is the probability of 5 year disease free survival?
Low risk group > 95%
Intermediate risk group > 90%
High risk group < 30% What role does partial tumor resection play in NB?
As long as there is no N-MYC amplification, >50% resection of localized tumors (including stage 2 disease) keeps patients in the low risk group.

What is the adjuvant therapy for low risk disease?
Low risk disease is observed after resection, except in the situation where less than 50% of the tumor was resected or in the presence of organ or life threatening symptoms.

When is 4S disease considered intermediate risk?
when symptomatic, has unfavorable biologic characteristics (by Shimada/INPC) or DNA index=1, or when no tissue is obtained for evaluation.

What chemotheraputic agents are used for intermediate risk disease?
cyclophosphamide, doxorubicin, carboplatin, etoposide.
Patients with favorable histology receive 4 cycles, unfavorable histology receive 8 cycles (each three weeks apart).

What is the current COG protocol goal for intermediate risk NB?
Protocol ANBL0531: Aims at reducing chemotherapy by decreasing the number of cycles.

What are the main chemotherapy strategies for high risk NB?
1. combination of agents to decrease resistant tumor growth and improve synnergy
2. use of maximal tolerated dose/high dose intensity
3. Target therapy for minimal residual disease
for autologous BM transplant, cells are harvested after second cycle of chemotherapy.
after neo-adjuvant therapy, resection re-evaluated after 5th cycle

What is the current COG protocol for high risk NB?
Protocol ANB0532: looks at role of further intensification of myoablative therapy, effect of radiation on residual and metastatic disease, test the effect of dose-intensified topotecan containing induction therapy.

How is response to therapy assessed?

1. volume (radiologic)
2. urine catecholamine levels
3. MIBG scans

Who are the patients who undergo surgical therapy alone without adjuvant therapy?

Most localized tumors with favorable histology:
stage 1 tumors
stage 2 A/B with no N-MYC amplification and >50% resection
stage 3 midline tumors completely resected with negative nodal disease

When is LN assessment not important in NB?

LN involvement in thoracic neuroblastoma does not affect risk classification, despite potential effect on staging

References: (Ashcraft textbook unless otherwise specified):
1. Ashcraft's Pediatric Surgery. 5th Edition. Chapter 68: Neuroblastoma
2. Okamatsu et al. Clinicopathologic characteristics of ganglioneuroma and ganglioneuroblastoma: A report from the CCG and COG. Pediatr Blood Cancer (2009) 53:563-9

4 mechanisms of esophageal injury by button batteries

Coins, the most commonly encountered ingested foreign body in children, cause complications related to chronic impaction and erosion. Button batteries are more dangerous. Methods by which they can cause damage (mostly when stuck in the esophagus) include

1. Toxic effect of mercuric oxide: some batteries contain lethal levels of mercuric oxide (5g). Batteries containing other heavy metals, lithium, or manganese are not toxic.
2. Electrical discharge from the battery
3. Pressure necrosis (as with coins)
4. Caustic injury from leakage of the battery's contents

Interestingly, batteries smaller than 1.6cm in diameter do not get lodged in the esophagus. Restricting the size of batteries produced to less than 1.6cm may help prevent serious injuries that can occur in as little as 5 hours after ingestion.

Reference:
Yardeni et al. Severe esophageal damage due to button battery ingestion: can it be prevented?
Pediat Surg Int (2004) 20:496