Severe acitretin-induced diffuse idiopathic skeletal hyperostosis: a case report.

Diffuse idiopathic skeletal hyperostosis (DISH), also known as Forestier-Rotes-Querol disease, is a systemic noninflammatory disease characterized by ossification of the entheses. DISH predominantly affects the spine. Although peripheral involvement is also often reported, it rarely affects patients' function. A 77-year-old man presented to our emergency department because of incapacitating pain and stiffness in the spine and hips. The patient had been diagnosed with biopsy-proven mycosis fungoides 3 years earlier and had been treated with oral acitretin at 25 to 50 mg daily since diagnosis. However, the patient gradually developed a severely limited range of motion in his spine and hips (left > right), significantly impairing his mobility and activities of daily living. Cervical and dorsolumbar radiographs showed extensive ossification along the anterior longitudinal ligament; this finding was compatible with DISH and had not been present in radiographs taken 3 years earlier. Pelvic radiographs showed multiple enthesophytes predominantly around the coxofemoral joints. DISH has been reported as a possible long-term adverse effect of acitretin. Despite optimal conservative treatment, the patient remained severely impaired and thus finally underwent extensive osteophyte excision and total hip replacement on the left side. His acitretin therapy was also stopped to prevent further progression of his DISH.