isotretinoin and Amyloidosis

Nodular amyloidosis is a primary cutaneous amyloidosis characterized by the deposition of amyloid L-type fibril proteins in the dermis. Clinical history and routine histology may not be sufficient to differentiate nodular amyloidosis from colloid milium. We present a case of a 45-year-old man with nodular amyloidosis, whose diagnosis was confirmed by the characteristic appearance of filaments on electron microscopy.

Topics: Acne Vulgaris; Amyloidosis; Dermatologic Agents; Diagnosis, Differential; Face; Facial Dermatoses; Humans; Isotretinoin; Male; Microscopy, Electron, Transmission; Middle Aged; Skin Diseases

Male Syrian golden hamsters received 12 weekly intratracheal exposures to 0.5% N-methyl-N-nitrosourea with a special catheter. Following exposures, animals were randomized into 4 groups of 63 hamsters and placed on diets of lab meal or meal with 120 mg 13-cis-retinoid acid (CRA)/kg, 327 mg ethyl retinamide (ER)/kg, or 343 mg N-(2-hydroxyethyl)retinamide (HR)/kg for 6 months at which time all hamsters were killed. The observed incidences of tracheal epithelial neoplasms (No. of animals with tumors/total No. of animals) were 10/63 (lab meal), 22/61 (CRA), 24/63 (ER), and 17/62 (HR). The incidence of carcinomas (No. of animals with tumors/total No. of animals) were 4/63 (lab meal), 12/61 (CRA), 12/63 (ER), and 11/62 (HR). The weight loss and mortality relative to those in the group fed the lab meal were significantly in the group fed HR but not in the other retinoid-treated groups.

Topics: Amyloidosis; Animals; Carcinoma; Cricetinae; Isotretinoin; Male; Mesocricetus; Methylnitrosourea; Neoplasms, Experimental; Precancerous Conditions; Probability; Tracheal Neoplasms; Tretinoin