Primary hypertrophic osteoarthropathy type 2 presenting as an acromegaly mimic with enteropathy

Primary hypertrophic osteoarthropathy (PHO) is a rare genetic disorder characterized by digital clubbing, pachydermia, and periostosis that frequently mimics acromegaly. Autosomal recessive pathogenic variants in SLCO2A1 cause PHO type 2 (PHOAR2) and are uniquely associated with chronic enteropathy associated with SLCO2A1 (CEAS). We report a 39-year-old male evaluated for acromegaly due to progressive coarse facies, cutis verticis gyrata, and profound limb clubbing. Endocrine workup demonstrated a normal growth hormone (GH) suppression test (GH nadir 0.76 ng/mL [SI: 0.76 µg/L]; reference range, <1 ng/mL [SI: <1 ug/L]) and a low-normal insulin-like growth factor 1 of 78 ng/mL (SI: 10.2 nmol/L) (reference range, 80-220 ng/mL [SI: 10.5-28.8 nmol/L]), attributable to nutritional suppression from chronic enteropathy, definitively excluding acromegaly. Severe microcytic anemia (hemoglobin 5.9 g/dL [SI: 59 g/L]; reference range, 13.0-17.0 g/dL [SI: 130-170 g/L]) resulted from gastrointestinal bleeding. Deliberate terminal ileoscopy identified an ulcerated ileocecal valve confirming CEAS. Radiography showed extensive periostosis and a normal sella turcica. Next-generation sequencing identified a homozygous SLCO2A1 pathogenic variant (c.764G>A, p.Gly255Glu), confirming PHOAR2-CEAS syndrome. Etoricoxib (120 mg daily) provided partial symptomatic relief. This case illustrates that digital clubbing in a patient with acromegaloid features mandates SLCO2A1 genetic evaluation, avoiding unnecessary pituitary investigation.