Thalidomide is effective in the treatment of such disabling dermatologic diseases as aphthosis, discoid lupus erythematosus, and prurigo nodularis, in which other drugs fail. However, its use can induce neuropathy necessitating caution in its administration. It was found in this electrophysiologic study of 13 patients that the data best revealing neuropathy, even when clinical abnormalities were not apparent, were reduction of sensory nerve action potential amplitude on the sural nerve, increase of somatosensory evoked potential latency following sural nerve stimulation, and reduction of sensory action potential amplitude on stimulating the median nerve at the wrist. In two patients, electrophysiologic abnormalities had increased after withdrawal, suggesting a prolonged action of thalidomide. Timely reduction of dosage, after detection of changes indicating the onset of side effects, could reduce the risk of the sometimes rapid emergence of clinical symptoms.

We report the case of a two patients who presented with a solitary, asymptomatic, angiomatoid nodule on the right thigh. Histopathological finding showed a poorly circumscribed lesion, located in the dermis. The morphological aspect strongly suggested the diagnosis of atypical fibrous histiocytoma (AFH), but surprisingly, the neoplastic cells were diffusely CD30+, with a membrane staining devoid of paranuclear dot. The lesions were tested for p80/ALK1 expression. Surprisingly, we found a diffuse cytoplasmic positivity. Interestingly, using break-apart fluorescent in situ hybridization (FISH), we evidenced an ALK rearrangement in nearly 50% of the neoplastic cells. The expression of CD30 and ALK1 with ALK gene rearrangement raised the possibility of three diagnoses: a primary cutaneous anaplastic large cell lymphoma (ALCL), a cutaneous inflammatory myofibroblastic tumor (IMT), an AFH of the skin associated with ALK gene rearrangement and CD30 positivity. The three hypotheses were discussed and finally, although p80/ALK1 expression and cytogenetic abnormalities in fibrous histiocytoma (FH) are not yet reported to the best of our knowledge, we favored the diagnosis of AFH.