Endocrine Abstracts

A 43-year-old female presented to the endocrine clinic with a 6-month history of polyuria and polydipsia. Investigations revealed a raised prolactin and a water deprivation test confirmed cranial diabetes insipidus. Subsequent pituitary MRI showed a likely pituitary microadenoma which however on further radiology review was thought to represent a hypothalamic/stalk lesion measuring up to 5 mm. She was commenced on intranasal desmopressin and cabergoline initially. Repeat MRI 2 years and 5 years post initial scan showed unchanged appearances to the stalk lesion. The patient found good symptom relief with desmopressin. A decision was made to stop cabergoline as this was not thought to be related to her stalk lesion. The patient had intermittent breathlessness which was investigated by lung function and a CT which did not show any interstitial lung disease but picked a borderline decreased transfer factor and low iron levels. The patient then subsequently developed intermittent haematuria which was investigated by a CT scan which showed mesenteric panniculitis and borderline mesenteric lymph nodes. Laparoscopic biopsy confirmed panniculitis with fibrosis while immunohistochemistry showed only a small number of IgG4 cells. A year later patient presented with features of an acute ischemic stroke from which she made an uneventful recovery. Over the next 2 years patient developed bilateral knee pain which appeared to get progressively worse. X-rays of her knees and a subsequent CT picked up expansile bony lesions in the distal femur and proximal tibia. She was investigated by haematology including a bone marrow biopsy which ruled out any plasma cell dyscrasias or metastases. The patient underwent a distal femoral biopsy which confirmed xanthomatous histiocyte infiltration of the trabecular bone and marrow spaces in keeping with a diagnosis of Erdheim-Chester disease. The patient had also noticed yellow deposits on her neck and face which appeared to have worsened subsequently. She was seen by dermatology who suspected large xanthelasma plaques and biopsy of the neck lesions confirmed the above diagnosis. A DNA analysis revealed an activating BRAF mutation, p. (Val600Glu) which is reported in more than 50% of patients with Erdheim-Chester disease which is a rare form of non-Langerhans-cell histiocytosis with the propensity to involve the following organs in decreasing order of frequency, namely long bones, maxillary sinus, large vessels, retroperitoneum, heart, lungs, central nervous system, skin, pituitary gland, and orbit. Our patient had endocrine manifestations preceding her eventual diagnosis a decade later.