Complete Pachydermoperiostosis With Acromegaloid Phenotype: Characteristic 99m Tc-Methylene Diphosphonate (MDP) Skeletal Scintigraphy in a Rare Clinical Mimic of Acromegaly

Pachydermoperiostosis (Touraine-Solente-Gole syndrome) is a rare disorder that can mimic acromegaly and should be considered a differential in patients with acromegaloid features. A 21-year-old man with acral enlargement, coarse facial features, joint pain, and hyperhidrosis, initially evaluated for acromegaly but eventually diagnosed as familial complete pachydermoperiostosis. 99m Tc-methylene diphosphonate skeletal scintigraphy showed increased perfusion, soft tissue and pericortical linear tracer uptake in the distal one third of tibiae, fibulae, and around the knee joint with periosteal thickening. The typical linear pattern of symmetrical tracer uptake at the end of long bones differentiates pachydermoperiostosis from secondary hypertrophic osteoarthropathy, which often shows asymmetric involvement.