Endocrine Abstracts

Introduction: Anterior pituitary cells are characterised by functional lineages based on the expression pattern of transcription factors. Functional differentiation in the form of pituitary adenomas co-secreting ACTH and growth hormone is very rare. We report a case of multiple cell line pituitary adenoma resulting in acromegaly and ACTH dependent Cushing’s.

Case: A 52-year-old woman of Ghanian origin (BMI of 57.5 kg/m²) presented with progressive unexplained weight gain, snoring, dental changes and enlargement of hands and feet. Her past medical history included hypertension, rheumatoid arthritis, sciatica, multinodular goitre and cataracts. The family history was insignificant. Blood tests showed elevated IGF-1, LH, FSH, prolactin, serum calcium, PTH with normal thyroid function and gut peptide hormone levels. An LDDST with CRH test revealed failure of cortisol suppression with an ACTH level of 44ng/l post CRH suggestive of ACTH dependent Cushing’s. Her growth hormone failed to suppress below 0.4 ng/ml on OGTT suggestive of co-existing acromegaly. A T2-weighted MRI brain with dynamic contrast imaging identified a pituitary lesion on the right side of the midline. IPSS was not conclusive. DOTATATE PET scan was normal and MEN-1 screen was negative. A neck sestamibi scan confirmed a right sided parathyroid adenoma. After trans-sphenoidal resection of the pituitary adenoma immunostaining was positive for synaptophysin, chromogranin, CK8/18, ACTH, TPIT with low proliferation rate for ki-67 and negative for prolactin, PIT1 and SF1. The overall appearances were most suggestive of a corticotroph adenoma however clinical expression of prolactin and growth hormone in addition to ACTH therefore remained unexplained.

Discussion: This case demonstrates a multiple cell line pituitary adenoma causing acromegaly with Cushing’s disease. A trans lineage expression of transcription factors as the underlying mechanism of this unique functional differentiation may explain the co-secretion of ACTH and growth hormone.

Keywords: Pituitary adenoma, Transcriptional factor, Acromegaly, GHoma, Cushing’s disease, ACTH dependant Cushing’s