Definition/General

Introduction:
-Neuroblastoma is the most common extracranial solid tumor in children
-It arises from neural crest cells in the adrenal medulla or sympathetic ganglia
-Represents 7-10% of all pediatric cancers
-FNAC shows characteristic small round blue cell morphology.
Origin:
-Arises from primitive neural crest cells
-Most commonly originates in adrenal medulla (40%)
-May arise from sympathetic chain ganglia
-Shows varying degrees of neural differentiation
-May undergo spontaneous regression (especially in infants).
Classification:
-Classified according to International Neuroblastoma Pathology Classification
-Favorable histology (differentiated, low MKI)
-Unfavorable histology (undifferentiated, high MKI)
-Ganglioneuroblastoma (mixed differentiation)
-Age-dependent prognostic significance.
Epidemiology:
-Peak incidence in first 5 years of life
-Median age 19 months
-Slight male predominance
-90% diagnosed before age 5
-Familial cases rare (<1%)
-Indian children show similar age distribution.

Clinical Features

Presentation:
-Abdominal mass (most common in adrenal primary)
-Bone pain (metastatic disease)
-Periorbital ecchymoses ("raccoon eyes")
-Opsoclonus-myoclonus syndrome (paraneoplastic)
-Horner syndrome (cervical/thoracic tumors)
-Failure to thrive.
Symptoms:
-Constitutional symptoms: Fever, weight loss, irritability
-Gastrointestinal: Diarrhea (VIP secretion), constipation
-Neurological: Weakness, paraplegia (spinal extension)
-Respiratory: Cough, dyspnea (thoracic tumors)
-Hypertension (catecholamine excess).

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Gross Description

Appearance:
-Large, lobulated mass replacing adrenal gland
-Gray-tan to pink cut surface
-Areas of hemorrhage and necrosis common
-Calcifications frequent
-Soft to firm consistency
-Encapsulated or infiltrative.
Characteristics:
-Variegated appearance with areas of differentiation
-Hemorrhagic and necrotic areas
-Cystic degeneration possible
-Calcifications ("eggshell" pattern)
-Gray-white areas (undifferentiated)
-Pink areas (differentiated).
Size Location:
-Variable size (2-20 cm at presentation)
-Adrenal medulla most common site
-May extend into retroperitoneum
-IVC involvement possible
-Lymph node metastases common
-Distant metastases at presentation (50%).

Microscopic Description

Immunohistochemistry

Positive Markers:
-Synaptophysin (strongly positive)
-Chromogranin A (positive in differentiated areas)
-NSE (neuron-specific enolase)
-Neurofilament
-S-100 (Schwannian elements)
-Tyrosine hydroxylase
-PHOX2B.
Negative Markers:
-Cytokeratins (negative)
-Leukocyte common antigen (CD45 negative)
-Desmin (negative)
-Myogenin (negative)
-WT1 (negative)
-CD99 (usually negative).
Diagnostic Utility:
-Neural marker combination (synaptophysin + chromogranin + NSE) diagnostic
-PHOX2B highly specific for neuroblastoma
-Neurofilament highlights neural differentiation
-S-100 highlights Schwannian stroma.

Molecular/Genetic

Differential Diagnosis

Sample Pathology Report

Template Format

Sample Pathology Report

Complete Report: This is an example of how the final pathology report should be structured for this condition.

Clinical Information

[Age] [months/years] old [male/female] with [abdominal mass/symptoms]. [Catecholamine levels] elevated

Specimen Information

FNAC from [adrenal mass/abdominal mass], performed under [guidance method]

Specimen Adequacy

[Adequate/Inadequate] for cytological interpretation

Cytological Findings

Smears showing [small round blue cells] in [loose clusters]. [Nuclear molding/High N:C ratio/Scanty cytoplasm] noted. [Rosettes/Neural differentiation] [present/absent]

Neural Differentiation

[Undifferentiated/Poorly differentiated/Differentiating] neuroblastoma features. [Homer Wright rosettes/Neuropil/Ganglion cells] [present/absent]

Background

Background shows [hemorrhage/necrosis/inflammatory elements]

Cytological Diagnosis

[Malignant small round cell tumor] - Features highly suggestive of neuroblastoma

Differential Diagnosis

Age-appropriate small round cell tumors include [Ewing sarcoma/lymphoma/other pediatric tumors]

Recommendations

URGENT pediatric oncology consultation. [Histopathological examination/Immunohistochemistry/Molecular studies] recommended

Note

Neuroblastoma requires immediate multidisciplinary pediatric oncology management. Age is critical prognostic factor