Background: Corticotrophin-releasing hormone (CRH) is the major regulator of adrenocorticotrophic hormone (ACTH) secretion from the anterior pituitary and acts via CRH-1 receptors (CRH-1R). Corticotropinoma though autonomous, still retain their responsiveness to CRH and hence, we hypothesize that in vivo detection of CRH-1 receptors on pituitary adenoma using Gallium-68 (68Ga)-tagged CRH can indicate the functionality of adenoma, and combining it with positron emission tomography-computed tomography (PET-CT) can provide requisite anatomical information. Methods: Subjects with ACTH-dependent Cushing’s syndrome (CS) (n = 27, 24 with Cushing’s disease [CD], 3 with ectopic CS [ECS]) underwent 68Ga CRH PET-CT. Two nuclear medicine physicians read these images for adenoma delineation and superimposed them on magnetic resonance imaging (MRI) sella. The information provided was used for intraoperative navigation and compared with operative and histopathological findings. Findings: 68Ga CRH PET-CT correctly delineated corticotropinoma in all the 24 cases of CD, including the 10 cases with adenoma size < 6mm (4 cases were negative on MRI). Corticotropinoma location on 68Ga CRH PET fusion images with MRI were concordant with operative findings and were further confirmed on histopathology. There was no tracer uptake in the pituitary in 2 patients with ECS, while, in another, the diffuse uptake in pituitary suggested ectopic CRH production. Conclusion: 68Ga CRH PET-CT represents a novel, noninvasive molecular imaging, targeting CRH receptors that not only delineate corticotropinoma and provides the surgeon with valuable information for intraoperative tumor navigation, but also helps in differentiating a pituitary from an extra-pituitary source of ACTH-dependent CS. Funding: None.

Background: Thyroid-stimulating hormone (TSH)-secreting pituitary adenoma (TSHoma) is the rarest functioning pituitary adenoma.Methods: A retrospective analysis of eight patients of TSHomas to highlight the presentations, diagnostic challenges, and treatment outcomes.Results: Median age at diagnosis was 42 years, median latency to diagnosis was 2.5 years, and thyrotoxic and compressive symptoms were the most common presenting symptoms. At presentation, three cases were plurihormonal, six cases were on medical treatment including thyroxine, and two cases were incidentally discovered. Imaging revealed macroadenoma in all cases. Seven cases underwent pituitary surgery, after which three achieved remission. Another case entered remission after adjunctive radiotherapy. Thyrotropin (TSH) immunostaining was demonstrated in six out of seven adenomas.Conclusion: TSHoma is a rare functioning pituitary tumor with both silent and symptomatic presentations. Diagnosis can be established with biochemical and imaging features, even without dynamic tests.

Thrombocytopenia as a precipitating factor for pituitary apoplexy (PA) is very rare event. There are only five reported cases of PA secondary to thrombocytopenia caused by underlying haematological malignancy. Herein, we report a case of 60‐year‐old male presenting with acute‐onset headache, bilateral vision loss, and ptosis. Computed tomography and magnetic resonance imaging revealed findings indicative of pituitary adenoma with apoplexy. He was noted to have thrombocytopenia, and bone marrow evaluation revealed precursor B‐lineage CALLA‐positive acute lymphoblastic leukemia. Accordingly, he was started on dexamethasone and vincristine but succumbed to Acinetobacter baumanii ‐related hospital‐acquired pneumonia two weeks after initiation of chemotherapy. We performed a literature search and found five cases of pituitary apoplexy secondary to haematological malignancy‐related thrombocytopenia. The usual age of presentation was in the 6 ^th to 7 ^th decade, and there was slight male preponderance. The underlying pituitary adenoma was either nonfunctioning or a prolactinoma, and in majority, the apoplexy event occurred after the diagnosis of haematological malignancy. The platelet counts at the time of PA were less than 30 × 10 ⁹ /L in all, and the malignancy subtypes were acute or chronic myeloid leukemia and chronic lymphoid leukemia. The current case highlights the importance of careful evaluation for the cause of thrombocytopenia in a case of PA.