No abstract

Twenty-seven cases of malignant peripheral nerve sheath tumors involving the head and neck region over a period of 7 years were reviewed. They were graded from 1-3 based on necrosis, mitosis, cellularity, and pleomorphism. Mean age of occurrence was 42 years, with a range of 12-70 years. Male preponderance was noted (M:F = 3.5:1). The most common site of involvement was the neck (44.6%). The main presenting symptom was an enlarging mass. The nerve of origin could be identified in 33% of patients. Treatment consisted of wide excision. The 5-year observed survival was 33%. Fifty-two percent of patients developed local recurrence of disease. Fifteen percent of patients died due to advanced local disease within 18 months of treatment. Distant metastasis was seen in 18.5% of patients. Lymph node metastasis was not seen. At the end of 5 years 15% of patients remained disease free. Large tumor size (> 5 cm) adversely affected the prognosis (P = < 0.1). No significant correlation was noted between the grade of tumor and survival.

Immunohistochemical staining was performed on 145 biopsies with a diagnosis of undifferentiated or poorly differentiated tumor in order to classify them into lymphoid, epithelial, or mesenchymal in origin. It was possible to arrive at a histogenetic diagnosis on immunostaining in 85.5% of cases. Immunostaining confirmed the diagnosis in 32.4% and contributed to diagnosis in 53.1%. Malignant lymphoma was the most common diagnosis (35.9%), followed by carcinoma (23.4%). A panel of antibodies consisting of anti-common leucocyte antigen (LCA), anti-epithelial membrane antigen (EMA), anti-cytokeratin (CK), anti-low to intermediate molecular weight cytokeratin (CAM 5.2), anti-S-100 protein (S-100), and anti-vimentin (VM) may resolve, to a large extent, some of the common diagnostic problems.

Desmoplastic small round cell tumor (RCT) is a relatively newly recognized neoplasm. It has a very distinct morphologic and high-grade polyphenotypic expression with a very poor prognosis. It is commonly seen in adolescent boys. We describe two cases of intra-abdominal desmoplastic small RCT in young girls (5 and 11 years of age). In both cases, the exact origin of tumor in the abdomen could not be established. Histopathologic examination of the biopsy specimens showed distinct desmoplastic stroma and coexpression of various epithelial, neural, and muscle markers. These two patients were treated primarily by debulking surgery followed by adjuvant chemotherapy (RCT II protocol). One of the two had a stable disease while the other had a progressive disease while on treatment. Thus our findings support the diverse histogenesis of this tumor and its poor prognosis.