Pachydermoperiostosis: Incomplete form, mimicking acromegaly

Sir, Read with interest the article, prevalence of colonic polyp and its predictors in patients with acromegaly. [1] Pachydermoperiostosis (PDP) or primary hypertrophic osteoarthropathy is a rare disorder that is characterized by digital clubbing and subperiosteal new bone formation associated with pain, polyarthiritis, cutis verticis gyrata, seborrhea, and hyperhidrosis. It is important to the endocrinologist as it needs to be distinguished from acromegaly. Considering its rarity, here, we describe a man who was referred to our center for acromegaly but had PDP. A 27‑year‑old male presented with enlargement of fingers and toes for the past 15 years. He was referred to our institute with a provisional diagnosis of acromegaly. He complained of pain over ankles and knees and hyperhidrosis for the past 2 years. He had been evaluated outside for acromegaly. His post‑glucose growth hormone suppression test was suppressible. His magnetic resonance imaging sella done outside was normal. He denied any history of the abnormal increase in height. He did not have any respiratory, cardiovascular, or gastrointestinal symptoms. There was no family history of similar illness. On examination, there was bulbous swelling of the tips of fingers and toes [Figure 1A‑C]. There was no frontal bossing or prognathism. His hemogram and biochemistry including C‑reactive protein and insulin‑like growth factor‑1 were within normal range. Radiological examination revealed extensive and symmetrical periosteal reaction in the bones of bilateral forearms and legs, small bones of hands, and feet feet [Figure a‑d, thin arrow]. The periosteal reaction involved diaphysis, metaphysis as well as epiphysis of long bones. There was bulbous appearance [Figure c and d, outlined arrow] of tips of fingers and toes due to increased soft tissue in that region. Thus, he had clubbing and periostitis with the absence of pachyderma, features suggestive of an incomplete form of PDP. His pain subsided with indomethacin. There are three clinical variants of PDP described: (i) Complete form, with pachydermia, clubbing and periostosis, (ii) incomplete form, with isolated periostosis and limited skin changes and (iii) fruste form, with predominant pachydermia and minimal periostosis. The disease starts at puberty, progresses variably to another 5–20 years and then remains stable. The disease course may be complicated by arthralgia, arthritis, and hemarthroses. A rare, but dreaded complication is myelofibrosis. Radiologically, there is periosteal new bone formation, the proliferation of soft tissues around tips of fingers and toes, acro‑osteolysis and calcifications of ligaments and interosseous membranes. Figure 1: (A‑C) Clinical …