The association of Sweet's syndrome with sarcoidosis.

We report a 43-year-old woman with biopsy proven Sweet's syndrome with massive mediastinal lymphadenopathy. No other clinical signs compatible with sarcoidosis were present. Mediastinoscopy was performed to establish a diagnosis. Histological evaluation revealed non-caseating granulomas compatible with sarcoidosis. We review the association of Sweet's syndrome and (haematological) malignancies, and eight other cases of Sweet's syndrome and sarcoidosis. All but one presented with erythema nodosum, making the diagnosis of acute sarcoidosis (Löfgren's syndrome) more likely than malignancy.

T-cell signet-ring cell proliferation in the skin simulating true histiocytic lymphoma.

We report the case of a solitary ulcerating lesion on the elbow of a 32-year-old man. Routine histopathological examination strongly suggested a histiocytic malignancy. However, electron-microscopical, enzyme-cytochemical, and immunological studies revealed that the "tumor" cells were T lymphocytes with an unusual (Leu 1+, Leu 3a+, Leu 4+, Leu 5b+, OKT4+, HLA-DR+, Ki-1+, Leu MI+) immunological phenotype and an even more uncommon morphology characterized by the development of giant multivesicular bodies giving some cells a signet-ring cell appearance, and autophagocytosis. The lesion healed spontaneously, notwithstanding its malignant histology.