Endocrine Abstracts

Introduction: Graves’ disease (GD) has a well-known association with thymic hyperplasia caused by TSHR expression in thymus and regresses by approximately 33-90% with treatment. Splenomegaly due to lymphoid hyperplasia has also been linked with GD in about 10% patients. Cerebral venous sinus thrombosis (CVST) linked with GD is documented in literature but is more common occurrence in solid cancers.

Case presentation: We report a case of 32-year man admitted under neurology with severe headaches, photophobia and weight loss. His MRI venogram confirmed thrombus within the great cerebral vein of Galen, straight sinus and proximal right transverse sinus. CT TAP showed 2.7 cm unilateral renal mass, 15.5 cm splenomegaly and 2 cm liver lesion confirmed as focal nodular hyperplasia on MRI liver. His TFT showed TSH < 0.01 mU/l, FT3 8.0 pmo/l (4.3-6.8) and FT4 21.5 pmo/l (7.7-15.1), Anti-TPO 170 iu/ml (n<10), TSI 0.30 iu/l (n<0.1). Connective tissue and antiphospholipid screen were negative. JAK-2 mutation was low level positive at 0.8, 0.9 and 1.2%. He underwent laparoscopic nephrectomy for G3, pT1a, R0 tumour. Histopathology confirmed renal cell carcinoma. His TFTs normalised with carbimazole and his repeat imaging 1 year later showed reduction in size of thymic tissue to 2.6 x 1.8 cm from initial 4.7 x 2.1 cm with normalization of splenomegaly on ultrasound.

Conclusions: Thymic hyperplasia, splenomegaly and cavernous sinus thrombosis in individual patients is an extremely rare occurrence and could possibly be due to GD in this case, which is supported by reduction in thymic size and resolution of splenomegaly with carbimazole. Moreover, small non-metastatic RCC is less likely to be a cause of his CVST. Haematology felt, that 1% JAK2 clone, which has not expanded in the past year, is unlikely to indicate myeloproliferative neoplasm and insufficient to offer an explanation of his CSVT.