Despite the high resolution of magnetic resonance imaging (MRI) of the pituitary gland, up to 40% of cases of Cushing's disease (CD) have normal MRI. Fused images of positron emission tomography and computed tomography (PET-CT) may have a potential diagnostic role in CD in general and in such cases in particular. Objective of this study is to explore the diagnostic potential of PET-CT for localization of adrenocorticotropin-secreting pituitary adenomas in CD. PET-CT was performed in 12 cases with de novo (7 cases) or persistent CD (5 cases) that were proven to have CD on biochemical, radiological and/or histopathological findings. These cases had a definite CD confirmed on histopathological and immunostaining examination of the subsequent transphenoidal surgical specimens (10 cases) and/or bilateral inferior petrosal sinus sampling (IPSS, 4 cases). PET-CT was positive in 7 of the 12 cases of CD (58%) showing a focal area of uptake in the pituitary gland. In these seven cases, MRI was positive in six (85.7%) but negative in one case (14.3%). In the other five cases with negative PET-CT, MRI was positive in two and negative in three cases. Of four cases with negative MRI, PET-CT was positive in one case (25%). We conclude that PET-CT is positive in around 60% of the cases of CD. Although the majority of cases with positive PET-CT had positive MRI, PET-CT may detect some cases with negative MRI and thus provides important diagnostic information. If these findings are confirmed in larger studies, PET-CT might become an important diagnostic technique, especially when the more invasive and technically demanding procedure of IPSS is not available or inconclusive.

Infarction of prolactin-secreting or growth hormone-secreting pituitary adenomas is not unusual. However, Infarction of ACTH-secreting adenomas has rarely been reported. Cyclical course of Cushing's syndrome alternating with adrenal insufficiency due to recurrent infarction of an ACTH-secreting pituitary adenoma has not been reported. We report here a 20-year-old lady who presented with florid signs of Cushing's syndrome but was found to have adrenal insufficiency on biochemical evaluation. Magnetic resonance imaging (MRI) of the pituitary gland showed that she had infarction of an ACTH-secreting macroadenoma. Over the next 6 years, her disease ran a cyclical course characterized by periods of hypercortisolism alternating with adrenal insufficiency due to repeated episodes of infarctions of the ACTH-secreting pituitary macroadenoma with corresponding changes in the pituitary adenoma on serial MRIs. The case alerts clinicians to this possibility when a patient presents with clinical picture of Cushing's syndrome but has adrenal insufficiency on biochemical testing. It also suggests that silent or subclinical infarction of pituitary adenomas is not uncommon and is probably under diagnosed.

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We describe a case of lingual thyroid (LT) with primary hypothyroidism, presenting during pregnancy and continuing beyond it with oropharyngeal obstructive symptoms and sleep apnoea syndrome (SAS) of mixed type. Although SAS of a combined obstructive and central type should not be too surprising in a case of LT with hypothyroidism, we were unable to find such a documentation previously. Only four weeks of L-thyroxin treatment resulted in a dramatic improvement in dysphagia, disturbed phonation, haemoptysis, arterial desaturation, sleep apnoea and overall sleep efficiency, in conjunction with a regression in the size of the lingual mass. This case highlights the vagaries confronted in the management of such a case and focuses on efforts towards accurate diagnosis and treatment.

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