Presentation of pseudohypoparathyroidism and pseudopseudohypoparathyroidism with skin lesions: Case reports and review

Atrophic violaceous plaques as the first manifestation of a disorder of GNAS inactivation

We report the case of a 10-month-old girl who presented with failure to thrive and multiple small atrophic violaceous plaques, with no other findings on her physical examination. The laboratory examinations, abdominal ultrasound and bilateral hand radiography performed were unremarkable. The skin biopsy revealed fusiform cells and focal ossification in the deep dermis. The genetic study showed a pathogenic variant of GNAS.

Intralesional sodium thiosulfate treatment of calcinosis cutis in pseudopseudohypoparathyroidism

Pseudopseudohypoparathyroidism is an imprinted GNAS spectrum disorder that induces the phenotype of Albright's hereditary osteodystrophy. This phenotype often involves the formation of calcinosis cutis: firm, painful cutaneous eruptions, which are classically difficult to treat. Intralesional sodium thiosulfate has been reported successfully in various cases of calcinosis cutis; however, these reports describe patients with autoimmune or idiopathic calcinosis. This case details the clinical improvement and resolution of calcinosis cutis lesions utilizing intralesional sodium thiosulfate in an adolescent patient with pseudopseudohypoparathyroidism.