Path Image
Undifferentiated neuroblastoma

Undifferentiated and poorly-differentiated neuroblastoma consists of small dark cells with little cytoplasm, which cannot be distinguished by other small blue round cell tumors. You must perform IHC stains to support the diagnosis. NSE (neural specific enolase), synpatophysin, CD56 ought to be positive.

A higher power image shows again small blue round cells, in a vaguely nested pattern with a small amount neuropil (neuritic processes which appear fibrillary) in the background.

Another higher power image demonstrating undifferentiated small round blue cells. Mature ganglion cells are not indentified, nor is there much neuropil. Both these features are found in the undifferentiated or poorly differentiated neuroblastoma.


Peripheral neuroblastic tumors (pNTs) arise from cells of the sympathetic nervous system, which are derived from neural crest cells. Thus, these tumors tend to be located along the path of neural crest migration such as the adrenal medulla, paraspinal sympathetic ganglia or the abdomen and thorax (often presenting as an abdominal mass).

pNTs consist of ganglioneuromas, ganglioneuroblastomas and neuroblastomas. These groups of tumors, especially neuroblastoma, have an unusual clinical course in that some of the tumors inexplicably regress, involute or mature. In fact, neuroblastomas may mature into a ganglioneuroma, which is benign lesion consisting mature ganglion cells and “Schwannian” stroma (a stromal background consisting of fibrillary Schwann-like cells). The usual benchmarks for aggressive tumor behavior such as positive surgical margins, necrosis, lymphovascular invasion and metastasis are not reliable prognostic indicators for pNTs.2

Neuroblastomas have unique prognostic factors which include age at diagnosis, clinical stage, histopathology, N-MYC oncogene status and DNA ploidy. Taking all these factors into consideration, patients are then categorized into 3 risk groups: low, intermediate and high. The pertinent prognostic features, briefly mentioned below, are well-detailed information in the 2007 article by Shimada and colleagues noted in the reference section.

Staging2 : The staging for neuroblastomas is very unique, as demonstrated by the fact that stage 1,2, and 4S (highly metastatic) are considered favorable stages.

pNT categorization2 : Basically, there are 4 categories which focuses on two features, the differentiation of the neuroblasts and the presence of Schwannian stroma. Favorable and favorable histologies depend the subtype of tumor and the addition of the MKI index (mitosis-karyorrhexis index).

Age: less than one year of age is favorable.

MYCN: amplification of this oncogene (>10 copies) indicates more aggressive tumor behavior

DNA index: Hyperdiploid tumors have a better prognosis than diploid tumors

Loss of chromosome 1p and or gain of 17q: unfavorable.

LDH, Ferritin and NSE: High serum levels are unfavorable.


One of the most common tumors of infancy and childhood, present in 1 in 7000 births. 1 Usually occurs in children with 40% of cases diagnosed at <1 year, 35% at 1-2 year and 25% older than 2 years of age. After age 10, the disease is extremely rare.3 Both genders affected equally.

Presents with an abdominal mass. Other symptoms include fever, pain, spinal cord compression and elevated VMA and HVA in urine.


Highly dependent on risk group, as determined by complex charts (see Background). Cure rate >90% for low-risk patients; 70-90% for intermediate-risk and 10-40% for high risk patients.1


Adrenal : Neuroblastoma


Adrenal : Ganglioneuroma


1 Thomspon LDR. Endocrine Pathology: Foundations in Diagnostic Pathology. Philadelphia, PA: Elsevier; 2006: 263-9.

2 Shimada H, Nakagawa A. Pathology of the Peripheral Neuroblastic Tumors. MedScape [Online]; published 1/12/2007. Available at Accessed on 7/28/09.

3 Lacayo NJ and Marina N. Neuroblastoma. Emedicine [Online]; updated 11/14/2007. Accessed on 7/28/2009. Available at

Last updated: 2011-08-27
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