Langerhans cell sarcoma with lineage infidelity/plasticity: a diagnostic challenge and insight into the pathobiology of the disease.

Langerhans cell sarcoma is a very rare and aggressive tumor of Langerhans cell lineage, for which aberrant expression of T-cell-related antigens has not yet been reported in a primary skin tumor. The authors describe the first known case of a primary cutaneous Langerhans cell sarcoma with lineage infidelity and use comparative genomic hybridization to investigate the genetic composition of the tumor and detect DNA copy number alterations throughout its entire genome. The case involves a 62-year-old woman who presented with an irregular nodule on the forehead surrounded by smaller lesions in its vicinity.

Deletion of the NF2 region in both meningioma and juxtaposed meningioangiomatosis: case report supporting a neoplastic relationship.

We report a case of juxtaposed atypical meningioma and meningioangiomatosis (MA) in an 8-year-old boy with no clinical stigmata or family history of neurofibromatosis. We studied the proliferative activity and genetic changes in the two lesions in an attempt to define their biologic and pathogenetic relationships. The MIB-1 index was 11% in the meningioma and <1% in the MA, indicating increased proliferative activity in the meningioma.

Rhabdomyosarcoma arising in a congenital melanocytic nevus.

A variety of malignancies have been reported to arise within congenital melanocytic nevi, most commonly malignant melanoma, but rarely rhabdomyosarcoma, liposarcoma, and malignant peripheral nerve sheath tumor as well. There have been only three documented cases of rhabdomyosarcoma arising within congenital melanocytic nevi: two embryonal rhabdomyosarcomas and one mixed liposarcoma and rhabdomyosarcoma. One of these cases was also associated with neurocutaneous melanosis.

Mullerianosis of inguinal lymph nodes: report of a case.

We report a case of florid mullerianosis involving inguinal lymph nodes, a simulator of metastatic adenocarcinoma. The patient was a 48-year-old woman with symptomatic leiomyomas and enlarged right inguinal lymph nodes. Microscopically two lymph nodes were partially or completely replaced by cystically dilated and small glands, many of which contained mucin.

Clear cell carcinoid tumor of the gallbladder: another distinctive manifestation of von Hippel-Lindau disease.

We describe a morphologically distinctive carcinoid tumor of the gallbladder that occurred in a 38-year-old man with von Hippel-Lindau (VHL) disease. The carcinoid tumor was composed predominantly of lipid-containing clear cells arranged in nests and tubules with pagetoid spread into the biliary epithelium and was interpreted as metastatic renal cell carcinoma. The neoplastic cells showed diffuse immunoreactivity for chromogranin, synaptophysin, cytokeratins (cytokeratin 7 and AE1/AE3) and, unexpectedly, for inhibin, but were negative for monoclonal carcinoembryonic antigen, serotonin and a variety of peptide hormones.

Expression of protein gene product 9.5 in epithelioid and conventional malignant peripheral nerve sheath tumors.

Context: Due to the frequent lack of S100 protein expression in malignant peripheral nerve sheath tumors (MPNSTs), especially the epithelioid variant, these tumors are difficult to diagnose without the aid of electron microscopy or a clinical history of neurofibromatosis.

Methods: Protein gene product 9.5 (PGP9.

Nasopharyngeal gangliocytic paraganglioma.

Gangliocytic paraganglioma (GP) is a rare neoplasm described almost exclusively in the gastrointestinal tract, especially the periampullary region. However, several examples have been reported at various sites, including the stomach, jejunum, and appendix. Herein we report a case of GP involving the nasopharynx.

Atypical bile duct adenoma, clear cell type: a previously undescribed tumor of the liver.

A variable proportion of bile duct adenomas of the liver are still confused with metastatic well-differentiated adenocarcinoma by surgeons and pathologists. We present here three examples of previously undescribed primary hepatic bile duct tumors that were composed almost entirely of clear cells that closely mimicked metastatic renal cell carcinoma. They were interpreted as atypical bile duct adenomas and occurred in two males and one female whose ages ranged from 25 to 64 years.

Adenomyofibroma of the endometrium with skeletal muscle differentiation.

A case of adenomyofibroma with skeletal muscle differentiation is described. A 55-year-old asymptomatic woman had atypical glandular cells of undetermined significance on a routine Papanicolaou smear. The endometrial biopsy revealed fragments composed of benign endometrial glands and myofibromatous stroma with foci of skeletal muscle differentiation.

Endometrial endometrioid carcinomas associated with Ewing sarcoma/peripheral primitive neuroectodermal tumor.

Three uterine tumors, each consisting of endometrioid carcinoma and Ewing's sarcoma/peripheral primitive neuroectodermal tumor (ES/pPNET) are described. The diagnosis of ES/pPNET in each case was first established in the hysterectomy specimen because each ES/pPNET was misinterpreted on the endometrial biopsy specimens as a high-grade homologous sarcoma. The ES/pPNET element in each case consisted of solid masses of small- to medium-sized round cells without Homer-Wright pseudorosettes, glial or ganglion cells, true rosettes with central lumens, or medulloepithelial tubules.

Uterine metastasis from a heterologous metaplastic breast carcinoma simulating a primary uterine malignancy.

Objective: To describe the first distant metastasis of a heterologous metaplastic breast carcinoma in the uterus and discuss its differential diagnosis.

Methods: Light microscopy, immunohistochemistry, and flow cytometry were used to evaluate the tumor.

Results: A 58-year-old woman underwent mastectomy for metaplastic breast carcinoma confined to the breast.

Clinical significance of negative and equivocal urinary bladder cytology alone and in combination with DNA image analysis and cystoscopy.

Background: We evaluated the individual and combined ability of cytology (CYT), image analysis (IA), and cystoscopy (CYSTO) to predict the presence of transitional cell carcinoma (TCC) at 6 months of follow-up in patients with or without a prior history of urothelial carcinoma and negative (NEG) or equivocal (atypical or suspicious) urinary CYT.

Methods: Fifty-one patients (43 with prior TCC) provided 57 urinary samples that were evaluated by CYT and DNA IA. Forty-nine patients were evaluated by CYSTO.