A 27 year old lady with a background of Langerhans cell histiocytosis (LCH) presented to endocrinology clinic for investigation of thyrotoxicosis. At the age of three years old, she presented with a rash on her forehead, which on biopsy revealed Langerhans cell histiocytosis. She was also noted to have symptoms consistent with diabetes insipidus, for which she remains on desmopressin therapy. At the age of six she received pituitary radiotherapy and 6 years ago developed secondary cortisol deficiency confirmed on an insulin tolerance test. Other medical history included PCOS and endometriosis for which she required assisted conception. More recently she developed fatigue, palpitations, diaphoresis and reported the development of asymmetry of the eyes. Clinical examination confirmed mild thyroid eye disease and signs consistent with thyrotoxicosis. Concordantly, her thyroid function test showed a suppressed TSH <0.01 mU/l (NR 0.34.2), fT3 11 pmol/l (NR 2.55.7), fT4 26 pmol/l (NR926) and TSH receptor antibody positivity at 1.3 u/ml (NR<0.4). A Technetium uptake scan was also consistent with Graves' thyrotoxicosis (overall uptake diffusely increased at 4.12%). She was managed with antithyroid medication and B-blockade. Whilst she remained thyrotoxic, her hydrocortisone replacement was increased to compensate for increased steroid metabolism. Discussion: Langerhans Cell Histiocytosis (LCH) is an uncommon condition which may involve the skin, bone, lung, lymph node, and the central nervous system most commonly. Involvement of the thyroid is rare and isolated involvement of the thyroid by LCH is even less common. Involvement of the thyroid may present as diffuse or nodular enlargement of the gland which may mimic thyroid malignancy. To our knowledge only one previous citation in an adult has reported the co-occurrence of LCH and Graves disease, although it is unclear whether there is a genuine association between the two conditions. (1) (1) Lassalle S, Hofman V, Santini J, Sadoul JL, Hofman P. Isolated Langerhans cell histiocytosis of the thyroid and Graves' disease: an unreported association. Pathology. 2008 Aug;40(5):5257. No abstract available.
Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.
Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.