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The diagnosis of extramedullary plasmacytomas (EMP) is usually easy to conform with immunohistochemical stains for kappa and lambda. In some cases, however, immunostains are problematic. In addition, prognostic features are not well described nor is it known whether EMP are associated with the Epstein-Barr virus. Therefore, 23 EMP of the head and neck (from 20 patients) were studied to (1) compare a non-isotopic paraffin section in situ hybridization technique for kappa and lambda mRNA with standard immunohistochemical techniques for assessing light chain expression, (2) compare the histologic grade to the proliferative fraction using an antibody for the proliferating cell nuclear antigen, and (3) determine the frequency of Epstein-Barr virus (EBV) association using probes for the EBV DNA (EBV NOT 1) and RNA (EBER-1). Light chain class restriction was demonstrated in 22/23 biopsies by in situ hybridization and in 21/23 biopsies by standard immunohistochemical techniques. Five of the six biopsies of well-differentiated EMP had proliferating cell nuclear antigen scores of 0 to 10% positive cells and one had 11 to 25% positive cells compared with greater than 75% in the one poorly differentiated EMP. Of 15 moderately differentiated EMP, 10 had proliferating cell nuclear antigen scores of 11 to 75%, and 5 had scores of greater than 75%. EBV DNA was detected in 1/23 biopsies and EBV RNA in 4/23 biopsies (3 patients). Thus, non-isotopic in situ hybridization is a useful technique to document clonality of plasma cells in routinely fixed, paraffin-embedded sections. Unlike routine immunohistochemistry, in situ hybridization avoids the problem of detecting stromal or nonspecific uptake of immunoglobulin.(ABSTRACT TRUNCATED AT 250 WORDS)

Introduction: We describe the clinicopathologic and flow cytometric features of 10 cases of basaloid squamous cell carcinoma (BSCC) of the head and neck to determine if DNA ploidy is a useful prognostic indicator. We also provide a review of 80 cases previously reported in the English language literature., Materials and Methods: The 10 cases were obtained from the surgical pathology files of Presbyterian University Hospital and The Eye and Ear Institute, Pittsburgh, PA (1987-1991). In all 10 cases, the microscopic slides and clinical data were reviewed. Flow cytometry was performed using the Hedley technique and formalin-fixed, paraffin-embedded tissue., Results: The mean age of patients with BSCC was 64 years (range, 49 to 75 years). Tumor involved the base of tongue (n = 5), hypopharynx-epiglottis (n = 3), and tonsil (n = 1). One case presented with cervical lymph node metastasis from an unknown primary site. Histologically, BSCC showed a biphasic pattern with basaloid-squamous elements, comedonecrosis, stromal hyalinization, surface dysplasia, and an in situ and/or invasive squamous cell carcinoma component. Flow cytometry revealed six diploid and four aneuploid tumors. Five of six patients with diploid and all four patients with aneuploid tumors developed early regional and/or distant metastases. Of the two patients who died of disease, one had a diploid and the other an aneuploid tumor., Conclusion: Our study reaffirms the predilection of BSCC for the base of tongue, pyriform sinus, and supraglottic larynx, and its aggressive biologic behavior with a high incidence of cervical lymph node metastasis (64%), distant spread (44%), and death from disease (38% mortality at 17 months median follow-up). However, in contrast to previous reports, tumor ploidy by flow cytometry provided no additional prognostic information beyond that supplied by routine histologic evaluation.

This paper describes the pathobiology of some of the more common skull base tumors. In addition to clinicopathologic features, emphasis is placed upon methods of diagnosis utilizing immunoperoxidase stains and molecular markers that may or may not impact upon prognosis.

Twenty-four fetal rhabdomyomas (FRMs) of the head and neck occurring in 16 male and seven female patients (sex unknown in one), ranging from 3 days to 58 years of age (median, 4.5 years) are reported. Ten patients (42%) were < or = 1 year old, six lesions (25%) were congenital, and 11 lesions (46%) occurred in patients > or = 15 years of age. The median tumor size was 3.0 cm (range, 1.0 to 12.5 cm). The FRMs presented as well-defined, solitary masses arising within the soft tissue or mucosa (2:1) of the head and neck. The median follow-up in 15 cases was 48 months (range, 2 months to 52 years) after diagnosis. With the exception of one patient with a local recurrence, all patients were either alive and well or dead of unrelated causes. Eight cases, regarded as "classic" FRM, consisted predominantly of bland, primitive spindled cells associated with delicate, elongated skeletal muscle cells reminiscent of fetal myotubules that were haphazardly arranged in an abundant fibromyxoid stroma. The remaining 16 cases, designated as "intermediate" FRM, displayed both a greater degree and a greater number of cells with skeletal muscle differentiation as well as a variety of distinctive cytologic and architectural features. These included the presence of large, ganglion cell-like rhabdomyoblasts with vesicular nuclei and prominent nucleoli, interlacing ribbon or strap-like rhabdomyoblasts with deeply acidophilic cytoplasm, broad bundles of more delicate spindled rhabdomyoblasts arranged in fascicles simulating smooth muscle, an occasional plexiform pattern with infiltration of adipose tissue and skeletal muscle, focal intimate association with peripheral nerves, and rare areas of fibroblastic proliferation. Mitoses were not found in 19 of the 24 FRM cases, but in five tumors there were 1 to 14 mitoses/50 high-power fields. Marked nuclear atypia, anaplasia, and a "cambium layer" were uniformly absent. The FRMs typically stained for myoglobin, desmin, and muscle-specific actin with focal or rare staining for vimentin, smooth muscle actin, S-100 protein, glial fibrillary acidic protein, and Leu-7. Cytokeratin, epithelial membrane antigen, and CD68 antigen (with KP1) were not detected. This study expands on previous reports of FRM and demonstrates that it has both a broader age range and histologic spectrum than previously recognized. The mitotic rates of FRM as well as certain histologic features overlap with rhabdomyosarcoma; the lack of marked nuclear atypia is an important distinguishing feature.(ABSTRACT TRUNCATED AT 400 WORDS)

Twenty-seven cases of adult rhabdomyoma (ARM) of the head and neck are reported. The 20 male and seven female patients ranged in age from 33 to 80 years (median age, 60 years). Symptoms included airway obstruction and a mass within the mucosa or soft tissue. Median tumor size was 3.0 cm (range, 1.5 to 7.5 cm). Seven patients (26%) presented with multinodular tumors and one tumor was multicentric. Follow-up was available in 19 cases and ranged from 2 months to 18.5 years after diagnosis (median, 6.0 years). Lesions recurred locally in eight cases (42%) 2 to 11 years after diagnosis (median, 6 years). One recurrence was multicentric. Histologically, ARM was composed of closely packed, large polygonal cells having abundant, eosinophilic, granular, or vacuolated glycogen-rich cytoplasm with focal cross-striations. Immunohistochemical stains confirmed skeletal muscle differentiation; the majority of tumors stained for myoglobin (21 of 21 tumors), muscle-specific actin (21 of 21 tumors), and desmin (19 of 21 tumors). Focal or rare immunoreactivity for vimentin (six of 17 cases), alpha-smooth muscle actin (17 of 20 cases), S-100 protein (14 of 21 cases), and Leu-7 (10 of 20 cases) also was detected. Cytokeratin, epithelial membrane antigen, glial fibrillary acidic protein, and CD68 antigen (with KP1) were not found. The characteristic histology and immunophenotype distinguish ARM from other lesions with which it is frequently confused, including granular cell tumor, hibernoma, oncocytoma, and paraganglioma. The expression of alpha-smooth muscle actin has not been reported previously in ARM; its presence could reflect aberrant expression of smooth muscle actin in skeletal muscle or possibly be a recapitulation of early skeletal muscle embryogenesis.

This article describes histopathologic and immunohistologic features of an epithelioid hemangioendothelioma that presented in the neck of a 40-year-old man. This tumor was unusual because of the presence of osteoclastlike giant cells scattered throughout the entire lesion. The tumor cells reacted positively for factor VIII-related antigen, and the osteoclastlike giant cells were reactive for KP1 antibody, a macrophage-associated antigen. We are aware of only one other previously reported example of soft-tissue epithelioid hemangioendothelioma with an abundance of osteoclast-like giant cells.

The term pyogenic granuloma (PG) is a misnomer. The histopathologic appearance is fairly characteristic, the lesion being in fact a lobular capillary hemangioma. The recognition of PG as a clinically polypoid or exophytic, circumscribed lesion is of importance to both the clinician and the pathologist, as this feature distinguishes PG from most malignant vascular tumors. Although PG may be multiple, especially on the skin, and necrosis is not uncommon, invasion of adjacent structures is not seen. Diagnostic pitfalls occur histologically when the characteristic lobular configuration of PG is not recognized because of a solid growth pattern of endothelial proliferation, the presence of brisk mitosis, intervascular stromal fibrosis or spindle cell proliferation, and occasionally an epithelioid appearance of endothelial cells. The different vascular neoplasms that may be confused with PG are discussed, and the clinical and histopathologic features of PG are emphasized.