Gouty tophi: a squamous cell carcinoma mimicker?

Background: Digital lesions can have a broad differential diagnosis. Squamous cell carcinoma (SCC), the most common digital malignant neoplasm, must be excluded as the cause of persistent digital lesions causing nail dystrophy.

Objective: To describe a patient with a periungual hyperkeratotic lesion on the left fifth digit which, upon initial dermatopathologic examination, appeared to be a malignancy.

Monoclonal antibody-based immunohistochemical diagnosis of rickettsialpox: the macrophage is the principal target.

Cutaneous biopsies of five eschars and two rash lesions from five patients from New York City with documented rickettsialpox were examined by immunohistochemical methods with a monoclonal antibody directed against spotted fever group rickettsial lipopolysaccharide for the presence and cellular location of Rickettsia akari Rickettsiae were identified in all of the five patients, with good concordance of results for the same biopsy tissues with previously reported results by the direct immunofluorescence method. In contrast with immunofluorescence, which did not reveal the location of the organisms, immunohistochemical examination demonstrated R. akari to be in perivascular cells, morphologically resembling macrophages.

Cutaneous cryptococcosis mimicking basal cell carcinoma in a patient with AIDS.

Background: Cryptococcosis is an opportunistic infection caused by the encapsulated yeast Cryptococcus neoformans. This ubiquitous organism has emerged as a frequent finding in immunosuppressed patients, especially those with underlying malignancies, organ transplants, and the acquired immune deficiency syndrome (AIDS). Cutaneous manifestations of cryptococcosis occur in 10 to 15% of patients having systemic involvement.

Cutaneous reaction to vasopressin.

Vasopressin (Pitressin, 8-arginine vasopressin) is a potent vasoconstrictor of splanchnic arterioles. When administered by continuous intravenous infusion, it reduces portal blood flow and pressure and is used in the management of bleeding esophageal varices. We describe a purpuric and necrotic cutaneous reaction to vasopressin that occurred at locations distant from intravenous catheter sites, and we review previous reports of similar reactions.