Primary hypertrophic osteoarthropathy (PHO) is a rare disease involving joint, bone and skin. Two underlying genes responsible for this disease-hydroxyprostaglandin dehydrogenase (HPGD) and solute carrier organic anion transporter family, member 2A1 (SLCO2A1)-are both associated with aberrant accumulation of prostaglandin E2 (PGE2). Cyclooxygenase-2 (COX-2) is a key enzyme in PGE2 synthesis. This study was intended to evaluate the safety and efficacy of COX-2 inhibitor in the treatment of PHO.

Primary hypertrophic osteoarthropathy (PHO) is a rare genetic multi-organic disease characterized by digital clubbing, periostosis and pachydermia. Two genes, HPGD and SLCO2A1, which encodes 15-hydroxyprostaglandin dehydrogenase (15-PGDH) and prostaglandin transporter (PGT), respectively, have been reported to be related to PHO. Deficiency of aforementioned two genes leads to failure of prostaglandin E2 (PGE2) degradation and thereby elevated levels of PGE2. PGE2 plays an important role in tumorigenesis. Studies revealed a tumor suppressor activity of 15-PGDH in tumors, such as lung, bladder and breast cancers. However, to date, no HPGD-mutated PHO patients presenting concomitant tumor has been documented. In the present study, we reported the first case of HPGD-mutated PHO patient with soft tissue giant tumors at lower legs and evaluated the efficacy of selective COX-2 inhibitor (etoricoxib) treatment in the patient.

Primary hypertrophic osteoarthropathy (PHO) is a hereditary bone disease that is grouped into PHO autosomal recessive 1 (PHOAR1) and PHO autosomal recessive 2 (PHOAR2) due to different causative genes. Data comparing bone microstructure between the two subtypes are scarce. This is the first study to find that PHOAR1 patients had inferior bone microstructure compared with PHOAR2 patients.

Primary hypertrophic osteoarthropathy (PHO) is an inherited disease characterized by digital clubbing, periostosis, and pachydermia. Based on two causative genes, hydroxyprostaglandin dehydrogenase (HPGD) and solute carrier organic anion transporter family member 2A1 (SLCO2A1), PHO is categorized into two subtypes: hypertrophic osteoarthropathy, primary, autosomal recessive 1 (PHOAR1) and hypertrophic osteoarthropathy, primary, autosomal recessive 2 (PHOAR2). In this study, we summarized the clinical manifestations and analyzed SLCO2A1 gene in 23 PHOAR2 patients in our center. As a result, 18 patients displayed complete phenotypes of PHO with digital clubbing, periostosis, and pachydermia. 29 mutations were found in total, and 22 of them were novel mutations including 13 missense, three nonsense, four deletion, one frame-shift and one splicing site mutations. Compared with nine PHOAR1 patients we previously reported, PHO patients with SLCO2A1 mutations were all male and presented with a later onset age. Peptic ulcers and myelofibrosis occurred only in PHOAR2 patients. The urinary level of prostaglandin E2 metabolite (PGEM) is significantly higher in PHOAR2 patients than that in PHOAR1 group. In conclusion, this study was the largest cohort to date to summarize PHOAR2 patients and to assess the phenotypic difference between two subtypes of PHO. The difference of urinary PGEM concentration between two subtypes is helpful for the differential diagnosis of PHO.