Unusual Breast Tumor in a Patient With McCune Albright Syndrome: A Case Report and Review of the Literature

Abstract

Introduction: McCune Albright syndrome (MAS) is a rare disorder classically defined by the triad polyostotic fibrous dysplasia (FD), café-aulait pigmentation of the skin and precocious puberty (PP). Other endocrinopathies can be associated with MAS and nonendocrine tissues such as breast may be involved. Case report: A 56-year-old woman was referred to our institution 20 years ago to treat a fast-growing infiltrative and ulcerative breast lesion, suspected as malignant. It was prompt operated and the 7 cm-tumor was classified as a bening "breast tubular adenoma". From the anamnesis it was evident café-au-lait spots (present soon after birth) and multiple osteoarticular manifestations from the age of 13: pain and functional impotency of the left limb, past femoral fracture, kyphoscoliosis and facial asymmetry. The patient had also episodes of tachydysrhythmias. Laboratorial tests revealed hypophosphatemia, hyperphosphaturia, elevation of serum bone markers and primary hyperthyroidism. The imaging studies showed multiple FD areas and several bone deformities. The most frequent GNAS somatic mutation was not detected in four different types of tissue studied. The patient was managed with bisphosphonates, calcitriol and oral phosphate, with significant improvement. The hyperthyroidism was treated with radioiodine. Discussion: We reported a MAS case with multiple endocrine and non-endocrine disease manifestations. The osseous disease is commonly the most prominent feature. Our patient had a unique fast-growing and infiltrative breast benign neoplasia, emphasizing the possible association of breast disorders in this setting. Genetic testing, not routinely available, may contribute little to the diagnosis and to the patient management.