Unusual associations of pachydermoperiostosis: a case report.

Primary hypertrophic osteoarthropathy (HOA), or pachydermoperiostosis, is a rare benign disorder of unknown etiology. It is characterized by clubbing, periosteal reaction, and thickening of the skin. Disease usually progresses slowly, and natural arrest may occur. Reported herein is the case of a 28-year-old male patient with progressively increasing swelling of large joints of lower limbs with severe anemia. He was diagnosed as a case of pachydermoperiostosis with myelofibrosis, which is a rare association. The development of myelofibrosis makes primary HOA a disease with unfavorable outcome.