Macular amyloidosis complicating macroprolactinoma--a novel clinical association

Amyloid deposition in the pituitary gland is a rare localised form of amyloidosis, and most commonly reported with prolactinoma. Macular amyloidosis is a rare form of localised cutaneous amyloidosis of obscure aetiology. In contrast to most localised amyloidosis, the precursor protein(s) of both macular amyloidosis and prolactinoma are unknown. A 35-year-old man with chronic headache (six years), blurring of vision (three years), and hyperpigmented macular lesion involving arms, legs, and back (two years) was diagnosed to have hyperprolactinaemia (8927 ng/mL) and secondary adrenal insufficiency. MRI revealed pituitary macroadenoma compressing the optic chiasma, encasing the right carotid artery and extending into the sphenoid sinus. A biopsy of skin from the right upper arm revealed thickened stratum corneum, acanthosis, and deposition of pale eosinophilic material in papillary dermis that gave a rose pink colour under methyl-violet and appeared congophilic with Congo red stain, which under polarised light showed green birefringence, diagnostic of macular amyloidosis. Headache, bitemporal haemianopia, and skin lesion improved following cabergoline therapy. Temporal profile of the disease characterised by symptoms of macroprolactinoma preceding onset of macular amyloidosis with resolution of symptoms of macroprolactinoma, accompanied by reductions in prolactin, and concomitant improvement in macular amyloidosis with cabergoline therapy may suggest some link between macroprolactinoma and macular amyloidosis. This report intends to highlight this novel association of macular amyloidosis and macroprolactinoma.