Desmoplastic malignant melanoma.

BACKGROUND: Desmoplastic malignant melanoma (DMM) is an uncommon variant of malignant melanoma and often is difficult to diagnose. Because of the relative rarity of this tumor, it has not been well studied and controversy remains concerning its biologic potential. OBJECTIVE: We compared survival rates of DMM with those of other malignant melanomas and determined what clinical and/or histologic features, if any, correlated with survival. METHODS: The files of the Armed Forces Institute of Pathology were searched for cases of DMM or related tumors with adequate material for further histologic and immunohistochemical evaluation. Follow-up on each patient was requested from the pathologist, clinician, and/or the patient. The follow-up was correlated with the histologic findings in each case. The relationship of histologic features to disease-free survival was evaluated. RESULTS: Adequate material for evaluation was available in 128 cases. The overall histologic features were similar to those previously reported. Immunohistochemical studies showed that all lesions were negative for HMB-45, a marker for premelanosomes. Factors that correlated with survival included tumor location, sex, tumor depth, and the presence of stromal mucin. The 5-year disease-free survival rate was 68% for all cases and 61% for lesions more than 4 mm deep. CONCLUSION: With a 5-year disease-free survival rate of 61%, DMM has a significantly better prognosis than other melanomas that have a 5-year disease-free survival rates of 40% to 41%. This may be related to neural differentiation of these tumors.

The recognition of recently described and potentially problematic melanocytic lesions of the skin.

Our attempt has been to examine unusual or problematic melanocytic lesions to enable the reader to recognize them histologically and to enhance the understanding of their biologic significance. An awareness of these lesions by the clinical dermatologist will, it is hoped, result in optimal patient management. The proper identification of melanocytic neoplasms is, and will continue to be, of prime importance to all concerned: the clinician, the dermatopathologist, and especially the patient.

Ischemic colitis complicating sickle cell crisis.

Abdominal pain is quite common in sickle cell crisis, although the cause of abdominal pain is seldom determined and remains controversial. We have recently seen an 18-yr-old man with sickle cell disease who developed acute abdominal pain during a crisis. Rebound tenderness on physical exam and "thumbprinting" on barium enema examination suggested possible colon infarction. Histopathologic review of the resected ascending colon demonstrated mucosal necrosis and submucosal edema consistent with ischemic colitis. Hypotheses regarding the cause of abdominal pain in sickle crises are reviewed; the pathophysiology of sickle-cell induced vasocclusion and its relation to the development of ischemic colitis in our patient is discussed.