Dermatitis herpetiformis, primary hypothyroidism and pituitary mass mimicking macroadenoma regression after treatment with thyroxin, corticosteroids and dapsone.

We report a case of 15-year-old girl who was diagnosed as a case of pituitary macroadenoma on computed tomography and magnetic resonance imaging (MRI) scans for her complains of diminished vision in the left eye and headache. On investigation she was found to have optic atrophy of left eye and primary hypothyroidism. She was started on thyroxin therapy in October 2008 and planned for transcranial excision of the tumor. Just before the date for planned surgery she developed mildly itchy vesico-bullous rash and the surgery was postponed. On histopathology and immunoflourescence studies it was confirmed to be the rash of dermatitis herpetiformis (DH) and treatment was started with corticosteroids in the last week of December 2008 and dapsone was added from mid January 2009. The lesions responded dramatically and within 6 weeks of starting treatment, she had become asymptomatic except for persisting diminution of vision. Repeat MRI scans in mid-February 2009 revealed total regression of pituitary mass. The case is being reported for interesting association of primary hypothyroidism, pituitary mass mimicking macroadenoma and DH; its successful outcome with medical management in the form of total regression of pituitary mass, thereby avoiding an unnecessary surgery.