Acrokeratosis paraneoplastica, also known as acrokeratosis paraneoplastica of Bazex or Bazex syndrome, is a paraneoplastic dermatosis characterized by scaly, erythematous plaques of the palms and soles as well as other acral sites including the ears, nose, and cheeks. It has been associated with several internal malignancies, but it is most commonly seen with squamous cell carcinomas of the upper aerodigestive tract and cervical lymphadenopathy from metastatic disease. Other malignancies that have been associated with acrokeratosis paraneoplastica include lymphomas, multiple myeloma, neuroendocrine tumors, small cell lung cancer, adenocarcinoma of the lung, hepatocellular carcinoma, thymus cancer, cutaneous squamous cell carcinoma, gastric or esophageal adenocarcinoma, and genitourinary cancers. Acrokeratosis paraneoplastica may appear prior to the diagnosis of an underlying malignancy.

Three stages of disease were originally delineated by Bazex and Griffiths:

• Stage I – Erythema and psoriasiform scaling of fingers, toes, and ear helices, and violaceous erythema with pityriasiform scaling of the nose. Nail changes include subungual hyperkeratosis, onychodystrophy, and onycholysis. Nail folds are involved and may be tender.
• Stage II – Palms and soles involved with keratoderma. Facial lesions involve upper lip and pinna. Symptoms and signs of malignancy usually present.
• Stage III – Legs, knees, thighs, arms, trunk, and scalp may be involved.