Histologic mimics of perineural invasion.

Background: Perineural invasion (PNI) by primary cutaneous cancers is an important adverse risk factor. Certain benign conditions may mimic microscopic PNI. Mohs surgery is being performed more frequently on smaller primary cutaneous malignancies.

Fine needle aspiration cytology of intraosseous ganglion: a case report.

Background: Intraosseous ganglia are histologically identical to their soft tissue counterparts. Fine needle aspiration cytology (FNAC) has been described for ganglia of soft tissue, but not for intraosseous ganglia.

Case: A 59-year-old woman was incidentally found to have a circumscribed, lytic lesion in the right scapular bone on radiographic studies performed for chronic impingement syndrome.

Cytology of cystic nephroma: a case report.

Background: Cystic nephroma is a rare benign multiloculated cystic renal neoplasm that is often confused with multicystic renal cell carcinoma radiographically and cytologically.

Case: A 58-year-old woman was incidentally found to have a multiloculated cystic right renal lesion. Cytologic examination of the fluid aspirated from the lesion was reported as highly suspicious for renal cell carcinoma, but a right nephrectomy revealed a cystic nephroma.

Fine-needle aspiration cytology of epidermoid cyst of the thyroid: report of a case and review of seven cases.

The cytological and histological features of a case of epidermoid cyst of thyroid are reported. Unlike the more common intrathyroid branchial cleft cyst, this lesion does not contain any lymphoid tissue. The presence of scattered small groups of smooth muscle fibers in the periepithelial fibrous tissue in this case suggests a teratomatous histogenesis.

Crush cytology of pituicytoma.

The crush cytology of a pituicytoma is reported. The lesion was resected from a 54-yr-old man with a 7-mo history of headache. The intraoperative crush smears revealed plump spindle cells with elongated, nonwavy nuclei, and moderate, finely granular cytoplasm with distinct cytoplasmic borders.

Extraneous cells of hepatic origin in adrenal fine needle aspiration as a diagnostic pitfall: a case report.

Background: The fine needle aspiration (FNA) cytologic evaluations of most adrenal lesions are straightforward. However, there are diagnostic pitfalls to be avoided.

Case: A 34-year-old, pregnant woman was discovered to have an asymptomatic, right upper abdominal mass on ultrasound examination.

Rhabdomyosarcoma in an adult presenting with nodal metastasis: a pitfall in fine-needle aspiration cytology of lymph nodes.

A 40-yr-old woman with an asymptomatic sinonasal rhabdomyosarcoma (RMS) initially presented with submental nodal metastasis. The fine-needle aspiration (FNA) and the subsequent biopsy of the nodal metastasis were misinterpreted as metastatic carcinoma because the primary tumor was occult, the tumor cells were exclusively round cells with a nested arrangement, and rhabdomyoblasts were absent. The correct diagnosis of metastatic RMS became apparent when the primary sinonasal tumor, detected in a CT, was biopsy proven to be an alveolar RMS.

Pigmented apocrine hamartoma of the vulva: a report of two cases.

Two cases of pigmented apocrine hamartoma of the vulva are reported; only one similar case involving the vulva was found in the literature. In each of the two cases, the lesion presented as a pigmented papule involving the labium minus of a young woman, and raised clinical concern for a malignant melanoma. On histological examination, the lesions were composed of tubules and cysts lined by melanin-containing apocrine cells and an outer layer of myoepithelial cells.

Metastatic carcinoma with myxoid stroma in the salivary gland: a case report.

Background: Most epithelial salivary gland tumors with a myxoid stroma are pleomorphic adenomas. Rare metastatic carcinomas have prominent myxoid stroma and therefore can mimic pleomorphic adenomas cytologically.

Case: A 62-year-old man presented with a left canthal tumor.

Liposarcoma of the colon: a case report.

A 52-year-old woman presented with abdominal pain and hematochezia. A colonoscopy showed a polypoid mass in the descending colon. A left hemicolectomy revealed a well-differentiated liposarcoma forming a polypoid intraluminal mass and an ill-defined nodule in the adjacent mesocolon.

Crush cytology of melanocytoma of the spinal cord. A case report.

Background: Primary melanocytic neoplasms of the central nervous system are rare. There is no previous report on the intraoperative crush cytology of these neoplasms.

Case: A melanocytoma occurred in a 65-year-old woman who presented with back pain, and weakness and numbness of the right lower extremity.

Reactive neuroepithelial aggregates of the skin.

A peculiar, apparently reactive, microscopic structure of the skin was observed in 5 patients. It is characterized histologically by a bundle of nerve fibers partially or completely ensheathed by bland nonkeratinizing squamous epithelium. In 2 patients, the specimens were reexcision specimens, in which this structure was found amid active postbiopsy repair.

Endometrioid adenocarcinoma arising from colonic endometriosis mimicking primary colonic carcinoma.

The clinicopathologic features of a case of endometrioid adenocarcinoma arising from colonic endometriosis that clinically and histologically mimicked a primary colonic carcinoma are reported. The differential diagnostic features of the tumor leading to the correct diagnosis included associated endometriosis, a minor mucosal component, focal squamous differentiation, absence of dirty necrosis, low nuclear grade, absence of a colonic adenoma, and a CK7+/CK20-/CEA- immunophenotype.

Endocervicosis of the small intestine.

A case of endocervicosis of the small intestine incidentally found as a mass lesion during a gastric bypass surgery is reported. No previous cases of intestinal endocervicosis have been reported in the literature.

Composite Large-Cell Neuroendocrine Carcinoma and Surface Epithelial-Stromal Neoplasm of the Ovary.

The clinicopathologic features of two cases of composite large-cell neuroendocrine carcinoma and surface epithelial-stromal neoplasm of the ovary are reported and those of eight previously published cases reviewed. The patients ranged in age from 22 to 77 years (mean, 56 years). The surface epithelial-stromal neoplasm was an endometrioid adenocarcinoma in one case, a mucinous cystadenoma in one case, and a mucinous adenocarcinoma in eight cases.