Gastrointestinal stromal tumors (GISTs) comprise a heterogeneous group of neoplasms of the gastrointestinal tract previously referred to as leiomyomas, leiomyosarcomas, or schwannomas. GISTs derive from the interstitial cell of Cajal and, in addition to variable expression of smooth muscle and neural markers, they characteristically express CD34 and CD117. To our knowledge, the cytologic appearance of gastric neoplasms designated as GISTs has never been reported. We illustrate the fine‐needle aspiration (FNA) cytology findings of a gastric stromal tumor having spindle cells with delicate cytoplasm and prominent nuclear palisading. Consistent core biopsy and immunochemistry findings further supported the diagnosis of GIST. Pathologic evaluation of the resected tumor confirmed the cytologic diagnosis. In the appropriate clinical and radiologic setting, a confident diagnosis of GIST can be established by FNA cytology and core biopsy. The roles of immunochemical stains and other ancillary techniques in reaching the correct diagnosis are addressed. Diagn. Cytopathol. 2000; 23:156–160. © 2000 Wiley‐Liss, Inc.

To determine if there is a significant difference in the relative frequency and degree of atypia of sporadic dysplastic nevi from the scalp, face, and neck area in children as compared with nevi from the rest of the body, we reviewed 99 consecutive biopsy specimens of melanocytic nevi from the scalp, face, and neck areas in children less than 18 years of age and compared them with 95 consecutive cases of nevi from other areas of the body in children of the same age. Large numbers of the nevi biopsied from the scalp (13 of 31; 41.93%) and forehead (2 of 10; 20%) were dysplastic. The number of dysplastic nevi from the neck (1 of 58; 1.72%) was not assessed as very different from the incidence found in other regions of the body, where 7 dysplastic nevi (7.36%) from a total of 95 nevi were found. Of the 13 dysplastic nevi from the scalp, 9 showed minimal atypia and 4 showed moderate atypia. No nevi with severe atypia were found. Many pigmented nevi from the scalp and forehead in children in this study were dysplastic. This finding points out the importance of examining the scalp of children for the presence of dysplastic nevi. The majority of nevi from the neck were common nevi.

We report three cases of desmoplastic trichoepithelioma (DTE) with overlying pseudocarcinomatous hyperplasia. All three cases developed on the face of patients in their second decade. In spite of their young age, a diagnosis of squamous cell carcinoma was considered for each case, given the unusual juxtaposition of these two well-known simulators of malignancy. Awareness of this potential association may avert a misdiagnosis of malignancy.

Patients with Li-Fraumeni syndrome (LFS) have a germ-line mutation of p53 (TP53) and are predisposed to develop a variety of malignancies at an early age. In this report, we describe an 18-year-old woman with LFS who developed an atypical fibroxanthoma (AFX) on her left arm. This tumor was based in the dermis, sparsely cellular and had ill-defined borders. It was composed predominantly of medium-sized spindled-shaped cells, but many large cells with pleomorphic nuclei were also present. Immunohistochemical stains showed that the tumor cells lacked expression of keratin, S-100 protein, desmin and CD34. Array-based comparative genomic hybridization (aCGH) revealed marked genomic instability with multiple whole chromosome losses, including chromosomes 8, 10, 13 and 22, as well as a partial loss of 17p. This represents one of a few reports of a cutaneous tumor in a patient with LFS and a rare example of an AFX occurring at a young age.