Detection of isolated tumor cells in neuroblastoma by immunohistochemical analysis in bone marrow biopsy specimens: improved detection with use of beta-catenin

Rapidly Progressive Ocular Proptosis as the First Sign of Neuroblastoma in a 16-Month-Old Child: Case Report and Review of Literature

Neuroblastoma (NB) is a malignant neoplasm accounting for 7.5% of malignancy in children. It can originate anywhere along the sympathetic chain with the adrenal medulla being the most common site in 35% of cases. The initial presentation of orbital metastasis is very unusual that accounts for only 8% of all NB cases. We report a rare case of a 16-month-old girl who initially presented with bilateral rapidly progressive ocular proptosis for two weeks. CT scan of the brain and orbits revealed bilateral heterogeneous lateral orbital lesions, and CT scan of the abdomen and pelvis revealed huge heterogeneous right adrenal lesions. Histopathology of the abdominal mass confirmed the diagnosis of stage IV NB with orbital metastasis and the patient was started on an aggressive chemotherapy regimen. Ophthalmologists have a vital role in the diagnosis of NB which should be considered in the differential diagnosis of any rapidly progressive proptosis in young children. Early investigation and systemic workup should be made immediately, as it is a potentially life-threatening malignant tumor that requires aggressive management.

Improving Detection of Metastatic Neuroblastoma in Bone Marrow Core Biopsies: A Proposed Immunohistochemical Approach

Bone marrow (BM) nvolvement is common in stage 4/M neuroblastoma patients and profoundly impacts clinical decision-making and predicts outcomes, but to our knowledge no standard exists for immunohistochemical evaluation of staging BMs. We examined the use of three immuno-stains-synaptophysin, tyrosine hydroxylase (TH), and PGP9.5-in detecting metastatic neuroblastoma in BM. We retrospectively selected 174 BM core biopsies from 41 neuroblastoma patients. Immunohistochemistry for synaptophysin, TH, and PGP9.5 was performed. These slides and the hematoxylin and eosin (H&E)-stained slide from each BM were randomized and independently scored by three pathologists as positive, negative, or indeterminate. Cohen's κ coefficients (interobserver agreement), McNemar's test (for frequencies of positive/indeterminate interpretations), and sensitivities for each stain/combination were calculated. Interobserver agreement was higher for all immunostains (synaptophysin, 78%-90%, κ  =  0.548-0.787; TH, 77%-92%, κ  =  0.481-0.788; and PGP9.5, 83%-90%, κ  =  0.601-0.740) than for H&Es (77%-84%, κ  =  0.434-0.572). Indeterminate interpretations were more frequent with H&Es (8.9%) and synaptophysin (6.0%) than with PGP9.5 (3.5%) or TH (3.3%). TH (76%) and PGP9.5 (70%) were the immunostains most likely to correctly resolve indeterminate H&E interpretation. Mean sensitivity among all three pathologists for detection of metastasis compared to the consensus diagnosis was 42.5% for H&E alone, 70.7% to 78.8% for H&E plus one immunostain, and 81.6% to 85% for H&E plus two immunostains. Immunohistochemistry enhanced sensitivity for tumor detection particularly dramatically in cases of prior chemotherapy. PGP9.5 and TH showed good interobserver agreement, fewer indeterminate interpretations, and resolved indeterminate H&E diagnoses at the highest frequencies. Therefore, we recommend H&E and two immunostains, specifically PGP9.5 and TH, for optimal detection of metastatic neuroblastoma in BM.

Diagnostic utility of PHOX2B in primary and treated neuroblastoma and in neuroblastoma metastatic to the bone marrow

CONTEXT

Neuroblastoma (NB) is the most common extracranial tumor of childhood. Although most cases have a distinctive histology, a subset of primitive cases require immunohistochemical studies to distinguish them from other small round blue cell tumors of childhood. Immunohistochemistry is also used to detect small amounts of tumor metastatic to the bone marrow and in posttreatment samples with obscuring fibrosis, calcification, or inflammation. The transcription factor PHOX2B is essential for the differentiation and survival of sympathetic neurons and chromaffin cells, and therefore is highly specific for the peripheral autonomic nervous system.

OBJECTIVE

To determine the diagnostic utility of PHOX2B immunohistochemistry as a marker of primary, treated, and metastatic NB.

DESIGN

Neuroblastoma tissue microarrays were stained with PHOX2B, CD57, and synaptophysin. Arrays containing rhabdomyosarcoma, Ewing sarcoma, and Wilms tumor were stained with PHOX2B, and negative bone marrow samples were stained with PHOX2B and CD57.

RESULTS

PHOX2B and CD57 were similar to synaptophysin in their ability to detect NB. PHOX2B and CD57 similarly showed robust staining in posttreatment NB and NB metastatic to the bone marrow. In contrast to the cytoplasmic staining pattern seen with synaptophysin and CD57, clear and strong nuclear PHOX2B permitted identification of individual tumor cells. PHOX2B staining was absent in all cases of rhabdomyosarcoma, Ewing sarcoma, and Wilms tumor, and in the negative bone marrow.

CONCLUSIONS

PHOX2B and CD57 are useful markers of NB. PHOX2B is specific for NB in its differential diagnosis with other small round cell tumors, and its nuclear staining may be helpful for accurate bone marrow tumor quantification.