Classification of melanoma in adults and children.

After a brief history of the classification of melanoma in adults, this chapter describes the major features of the classic histogenetic types as well as of uncommon variants. Particular attention is paid to the meaning of controversial terms such as "minimal deviation" and "borderline." Specific problems associated with the classification of melanoma in children are also addressed, along with interpretation of atypical lesions resembling Spitz nevi.

Scarless wound repair: a human fetal skin model.

Animal studies demonstrate that the fetus heals cutaneous wounds by reformation of normal tissue architecture without scar formation. We have developed a new model to study human fetal skin wound healing. Grafts of human fetal skin placed onto athymic mice retain the morphologic features of normal development, although they differentiate at an accelerated rate when placed cutaneously compared to subcutaneously. Full-thickness skin grafts from human fetuses at 15 (n = 12), 17 (n = 11), 18 (n = 25), 19 (n = 20) and 22 (n = 13) weeks gestational age were placed onto athymic (nu/nu) mice in 2 locations: (1) cutaneously onto a fascial bed and thereby exposed to air or (2) subcutaneously in a pocket under the murine panniculus carnosus. Linear incisions were made in each graft 7 days after transplantation. Grafts were harvested at 7, 14 and 21 days postwounding and analyzed histologically for scar formation. By hematoxylin & eosin and Mallory's trichrome stains, complete epidermal and dermal graft wound healing without scar formation was demonstrated in the subcutaneous grafts at each gestational age studied. In contrast, scar was seen at all time points in the cutaneous grafts in both the incisional wound and at the interface of the fetal human skin graft and adult mouse skin, regardless of fetal skin gestational age.(ABSTRACT TRUNCATED AT 250 WORDS)

MR imaging of spindle cell hemangioendothelioma.

Spindle cell hemangioendothelioma is a slowly progressing vascular tumor of low grade malignancy. This neoplasm has been reported in 33 patients but in only one patient were osseous lesions seen. The only other description regarding imaging of this tumor was CT demonstrating soft tissue masses in the thigh without osseous involvement. We present a case of spindle cell hemangioendothelioma in which magnetic resonance further defined the radiographic features of this newly recognized tumor.

Clinical and pathological features of bacillary peliosis hepatis in association with human immunodeficiency virus infection.

BACKGROUND: Peliosis hepatis is characterized by cystic, blood-filled spaces in the liver and is seen in patients with chronic infections or advanced cancer and as a consequence of therapy with anabolic steroids. Cutaneous bacillary angiomatosis is a bacterial infection that occurs in patients with human immunodeficiency virus (HIV) infection; its histologic appearance is that of a pseudoneoplastic vascular proliferation. METHODS: We studied liver tissue from eight HIV-infected patients with peliosis hepatis, two of whom also had cutaneous bacillary angiomatosis. For comparison we examined tissue from four patients who had peliosis hepatis without HIV infection. Tissues were examined histologically on routine sections and with special stains and electron microscopy. RESULTS: The histologic features seen in peliosis hepatis associated with HIV infection, but not in the four cases unrelated to HIV infection, were myxoid stroma and clumps of a granular purple material that on Warthin-Starry staining and electron microscopy proved to be bacilli. The bacilli, which could not be cultured, were morphologically identical to those found in the skin lesions of cutaneous bacillary angiomatosis. The clinical courses of two of the patients with this "bacillary peliosis hepatis" indicate that it responds to antibiotic treatment. CONCLUSIONS: HIV-associated bacillary peliosis hepatis is an unusual, treatable opportunistic infection, probably caused by the same organism that causes cutaneous bacillary angiomatosis. Our failure to find bacilli in non-HIV-associated cases implies that other pathogenetic mechanisms may also be responsible for peliosis hepatis.

Hematologic aspects of human immunodeficiency virus infection: laboratory and clinical considerations.

Hematologic abnormalities are common in patients with HIV infection. This review will focus on HIV-associated cytopenias and coagulation abnormalities. Their occurrence, laboratory evaluation, and clinical significance and the mechanisms underlying their development are discussed. Therapeutic modalities are presented, with an emphasis on treatment strategies for HIV-associated thrombocytopenia.