Colonic melanoma, primary or regressed primary.

Primary melanoma originating in the gastrointestinal tract is very rare and the majority of these tumors arise in the mucosa of the anus or rectum. A case of solitary colonic melanoma in a 79-year-old man is described with a review of pertinent literature. The surgically excised neoplasm was evaluated by routine histology and immunohistochemistry stains. Pathologic examination of the excised cecal mass revealed an 8 x 5-cm tan-pink mass with a central green-black necrotic area. Histologically, there were solid sheets of S100- and HMB-45-positive pigmented cells extending from the mucosal ulcerated surface through the bowel wall. The patient had no evidence of cutaneous or ocular primary melanoma. He remained free of recurrent disease 5 years after surgical resection of the colonic melanoma. The unique pathologic features and clinical outcome support the diagnosis of primary colonic melanoma in this patient.

Tissue factor promotes melanoma metastasis by a pathway independent of blood coagulation.

Several studies have established a link between blood coagulation and cancer, and more specifically between tissue factor (TF), a transmembrane protein involved in initiating blood coagulation, and tumor metastasis. In the study reported here, a murine model of human melanoma metastasis was used for two experiments. (i) The first experiment was designed to test the effect of varying the level of TF expression in human melanoma cells on their metastatic potential. Two matched sets of cloned human melanoma lines, one expressing a high level and the other a low level of the normal human TF molecule, were generated by retroviral-mediated transfections of a nonmetastatic parental line. The metastatic potential of the two sets of transfected lines was compared by injecting the tumor cells into the tail vein of severe combined immunodeficiency (SCID) mice and later examining the lungs and other tissues for tumor development. Metastatic tumors were detected in 86% of the mice injected with the high-TF lines and in 5% of the mice injected with the low-TF lines, indicating that a high TF level promotes metastasis of human melanoma in the SCID mouse model. This TF effect on metastasis occurs with i.v.-injected melanoma cells but does not occur with primary tumors formed from s.c.-injected melanoma cells, suggesting that TF acts at a late stage of metastasis, after tumor cells have escaped from the primary site and entered the blood. (ii) The second experiment was designed to analyze the mechanism by which TF promotes melanoma metastasis. The procedure involved testing the effect on metastasis of mutations in either the extracellular or cytoplasmic domains of the transmembrane TF molecule. The extracellular mutations introduced two amino acid substitutions that inhibited initiation by TF of the blood-coagulation cascade; the cytoplasmic mutation deleted most of the cytoplasmic domain without impairing the coagulation function of TF. Several human melanoma lines expressing high levels of either of the two mutant TF molecules were generated by retroviral-mediated transfection of the corresponding TF cDNA into the nonmetastatic parental melanoma line, and the metastatic potential of each transfected line was tested in the SCID mouse model. Metastases occurred in most mice injected with the melanoma lines expressing the extracellular TF mutant but were not detected in most mice injected with the melanoma lines expressing the cytoplasmic TF mutant. Results with the extracellular TF mutant indicate that the metastatic effect of TF in the SCID mouse model does not involve products of the coagulation cascade. Results with the cytoplasmic TF mutant indicate that the cytoplasmic domain of TF is important for the metastatic effect, suggesting that the TF could transduce a melanoma cell signal that promotes metastasis.

Mucinous syringometaplasia with prominent epithelial hyperplasia and deep dermal involvement.

This report describes two patients with mucinous syringometaplasia whose findings expand the microscopic and clinical spectrum of the entity. The first patient had an eroded nodule that exhibited multiple epidermal invaginations that penetrated deeply into the dermis. In addition to mucinous metaplasia, there was also exuberant papillary epithelial hyperplasia. Expanded eccrine ducts with similar changes appeared as lobules isolated in the dermis but were shown to connect with the invaginations. In the second patient, a clinical "cyst" drained serous fluid. Multiple papillary-cystic epithelial lobules similar to those seen in the first case were located in the dermis. A few approached the epidermis, but epidermal connections were not identified. The epithelium in these lesions was identical to that previously described in mucinous syringometaplasia. The tumors differed from prior cases by virtue of the number of eccrine apparatus involved, the extent and depth of involvement, and the presence of prominent papillary epithelial hyperplasia.

A histiocytoid (epithelioid) vascular tumor of the ovary: occurrence within a benign cystic teratoma.

This report describes the case of a 22-yr-old woman with benign cystic teratomas of both ovaries. One of the teratomas contained a histiocytoid (epithelioid) vascular tumor. The lesion was composed of closely arranged, variably canalized, nests and cords of vacuolated, histiocytoid endothelial cells. Nuclear morphology was relatively uniform, but four to six mitotic figures were found per ten high-power fields. Stromal inflammatory cells were notably sparse. Intravascular growth was absent. The patient remained well 30 mo after surgery. The authors review the literature concerning vascular tumors of the ovary and comment on histiocytoid vascular lesions in general.

Lymphomatoid papulosis terminating as cutaneous T cell lymphoma (mycosis fungoides).

The 26-year-course of a T cell dysplasia is described in a patient who during his illness showed an evolution from the clinical features of lymphomatoid papulosis to tumor-stage mycosis fungoides with dissemination to nodes and viscera.

Electron-probe microanalysis. Aid in the study of skin granulomas.

Several causes of noncaseating epithelioid granulomas of the skin must be considered before the diagnosis of sarcoidosis can be made. We report here three such cases that were studied retrospectively with scanning electron microscopy in combination with backscattered electron imaging and x-ray energy spectrometry. Inorganic particles were identified in the granulomas of two patients, illustrating that these techniques are valuable aids in establishing the cause of granulomas.

Basal cell epitheliomas after repeated fluoroscopic examinations of the chest.

In two patients who received artificial pneumothorax therapy for pulmonary tuberculosis, many basal cell epitheliomas on the thoracic skin developed 26 and 30 years later. Pneumothorax therapy as done in the 1930s and 1940s required frequent fluoroscopic examinations of the chest for several years, resulting in a considerable cumulative dose of radiation. Skin cancer may now be developing in predisposed individuals after an average latent period of 25 years, making it likely that more of these patients will come to our attention.