Osteoma cutis in Pseudohypoparathyroidism

Abstract

Pseudohypoparathyroidism (PHP) is a hereditary disorder characterized by an end-organ resistance for parathormone. PHP can be classified into different types by biochemical and phenotypic characteristics and the level of the defect in the hormone-receptor complex. PHP is described as Albright’s hereditary osteodystrophy (AHO) when a specific phenotype is present. We report a case of osteoma cutis in a 30-year-old woman with AHO. Successful treatment was obtained by debriding the lesion followed by split-thickness skin grafting.

Osteoma cutis in pseudohypoparathyroidism

“…Sometimes there may be a generalized membrane defect, which results in resistance to many other hormones activated by adenylyl cyclase pathway. This may explain associated conditions such as hypothyroidism (as in our case), hypogonadism and other endocrinological disorders 8,9 …”

“…Hence PHP and PPHP are considered as variable expressions of the same disease entity and may be seen at different stages in the same patient. Our patient had features of PHP type Ia and AHO with hypothyroidism 8,9 …”

“…Primary osteoma cutis is also seen in Albright's hereditary osteodystrophy (AHO) with or without pseudohypoparathyroidism (PHP). AHO is an X‐linked or autosomal dominant disorder first described by Albright in 1942 8 . [AHO is different from McCune–Albright syndrome, which is characterized by café‐au‐lait macules and polyostotic fibrous dysplasia, and in which bone is replaced by fibrous tissue resulting in asymmetry, bony growths and fracture, and endocrine dysfunction in the form of precocious puberty, hyperthyroidism, Cushing's syndrome, hypersomatotrophism, hyperprolactinaemia, and hyperparathyroidism.]…”

“…Learning difficulties are related to hypocalcaemia, hence the patients with the primary osteoma cutis should be assessed thoroughly for the underlying calcium abnormalities and treated. Patients should also be screened for evidence of other endocrinological abnormalities, especially hypothyroidism 8,9 …”

“…AHO is an X-linked or autosomal dominant disorder first described by Albright in 1942. 8 [AHO is different from McCune-Albright syndrome, which is characterized by café-au-lait macules and polyostotic fibrous dysplasia, and in which bone is replaced by fibrous tissue resulting in asymmetry, bony growths and fracture, and endocrine dysfunction in the form of precocious puberty, hyperthyroidism, Cushing's syndrome, hypersomatotrophism, hyperprolactinaemia, and hyperparathyroidism.] AHO is characterized by short stature, round facies, flattened nasal bridge, obesity, short stubby hands with brachydactyly (shortened fourth and fifth metacarpals and metatarsals) and short broad nails.…”