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Open access

Yew Wen Yap, Steve Ball and Zubair Qureshi

Summary

The coexistence of primary hypothyroidism and thyroid-stimulating hormone (TSH)-stimulating pituitary macroadenoma can be a rare occurrence and can make diagnosis very challenging. We describe a case of a 44-year-old female with a history of fatigue, poor concentration, weight gain and amenorrhoea together with biochemical evidence of primary autoimmune hypothyroidism. Her initial TSH levels were elevated with low normal free thyroxine (T4) levels. Levothyroxine treatment was initiated and the dose was gradually titrated to supraphysiologic doses. This led to the normalisation of her TSH levels but her free T4 and triiodothyronine (T3) levels remained persistently elevated. This prompted a serum prolactin check which returned elevated at 2495 µ/L, leading onto pituitary imaging. A MRI of the pituitary gland revealed a pituitary macroadenoma measuring 2.4 × 2 × 1.6 cm. Despite starting her on cabergoline therapy with a reduction in her prolactin levels, her TSH levels began to rise even further. Additional thyroid assays revealed that she had an abnormally elevated alpha subunit at 3.95 (age-related reference range <3.00). This corresponded to a thyroid-secreting hormone pituitary macroadenoma. She went on to have a transphenoidal hypophysectomy. Histology revealed tissues staining for TSH, confirming this to be a TSH-secreting pituitary macroadenoma. This case highlighted the importance of further investigations with thyroid assay interferences, heterophile antibodies, alpha subunit testing and anterior pituitary profile in cases of resistant and non-resolving primary hypothyroidism.

Learning points:

  • Levothyroxine treatment in primary hypothyroidism can potentially unmask the presence of a latent TSH-secreting pituitary macroadenoma, which can make diagnosis very challenging.

  • A high index of suspicion should prompt clinicians to further investigate cases of primary hypothyroidism which despite increasing doses of levothyroxine treatment with normalisation of TSH, the free T4 and T3 levels remain persistently elevated.

  • Clinicians should consider investigating for adherence to levothyroxine, thyroid assay interference, heterophile antibodies, TSH dilution studies, alpha subunit and anterior pituitary profile testing to further clarity the diagnosis in these patients.

  • Although coexistent cases of TSHoma with primary hypothyroidism are rare, it should always be in the list of differential diagnoses in cases of unresolving primary hypothyroidism.

Open access

Michelle Maher, Federico Roncaroli, Nigel Mendoza, Karim Meeran, Natalie Canham, Monika Kosicka-Slawinska, Birgitta Bernhard, David Collier, Juliana Drummond, Kassiani Skordilis, Nicola Tufton, Anastasia Gontsarova, Niamh Martin, Márta Korbonits and Florian Wernig

Summary

Symptomatic pituitary adenomas occur with a prevalence of approximately 0.1% in the general population. It is estimated that 5% of pituitary adenomas occur in a familial setting, either in isolated or syndromic form. Recently, loss-of-function mutations in genes encoding succinate dehydrogenase subunits (SDHx) or MYC-associated factor X (MAX) have been found to predispose to pituitary adenomas in co-existence with paragangliomas or phaeochromocytomas. It is rare, however, for a familial SDHx mutation to manifest as an isolated pituitary adenoma. We present the case of a pituitary lactotroph adenoma in a patient with a heterozygous germline SDHB mutation, in the absence of concomitant neoplasms. Initially, the adenoma showed biochemical response but poor tumour shrinkage in response to cabergoline; therefore, transsphenoidal surgery was performed. Following initial clinical improvement, tumour recurrence was identified 15 months later. Interestingly, re-initiation of cabergoline proved successful and the lesion demonstrated both biochemical response and tumour shrinkage. Our patient’s SDHB mutation was identified when we realised that her father had a metastatic paraganglioma, prompting genetic testing. Re-inspection of the histopathological report of the prolactinoma confirmed cells with vacuolated cytoplasm. This histological feature is suggestive of an SDHx mutation and should prompt further screening for mutations by immunohistochemistry and/or genetic testing. Surprisingly, immunohistochemistry of this pituitary adenoma demonstrated normal SDHB expression, despite loss of SDHB expression in the patient’s father’s paraganglioma.

Learning points:

  • Pituitary adenomas may be the presenting and/or sole feature of SDHB mutation-related disease.

  • SDHx mutated pituitary adenomas may display clinically aggressive behaviour and demonstrate variable response to medical treatment.

  • Histological evidence of intracytoplasmic vacuoles in a pituitary adenoma might suggest an SDH-deficient tumour and should prompt further screening for SDHx mutations.

  • Immunohistochemistry may not always predict the presence of SDHx mutations.

Open access

Ahmed Iqbal, Peter Novodvorsky, Alexandra Lubina-Solomon, Fiona M Kew and Jonathan Webster

Summary

Secondary amenorrhoea and galactorrhoea represent a common endocrine presentation. We report a case of an oestrogen-producing juvenile granulosa cell tumour (JGCT) of the ovary in a 16-year-old post-pubertal woman with hyperprolactinaemia amenorrhoea and galactorrhoea which resolved following surgical resection of the tumour. This patient presented with a 9-month history of secondary amenorrhoea and a 2-month history of galactorrhoea. Elevated serum prolactin at 7081 mIU/l and suppressed gonadotropins (LH <0.1 U/l; FSH <0.1 U/l) were detected. Serum oestradiol was significantly elevated at 7442 pmol/l with undetectable β-human chorionic gonadotropin. MRI showed a bulky pituitary with no visible adenoma. MRI of the abdomen showed a 4.8 cm mass arising from the right ovary with no evidence of metastatic disease. Serum inhibin B was elevated at 2735 ng/l. A right salpingo-oophorectomy was performed, and histology confirmed the diagnosis of a JGCT, stage International Federation of Gynaecology and Obstetrics 1A. Immunohistochemical staining for prolactin was negative. Post-operatively, oestrogen and prolactin levels were normalised, and she subsequently had a successful pregnancy. In summary, we present a case of an oestrogen-secreting JGCT with hyperprolactinaemia manifesting clinically with galactorrhoea and secondary amenorrhoea. We postulate that observed hyperprolactinaemia was caused by oestrogenic stimulation of pituitary lactotroph cells, a biochemical state analogous to pregnancy. To the best of our knowledge, this is the first report of hyperprolactinaemia as a result of excessive oestrogen production in the context of a JGCT.

Learning points

  • Hyperprolactinaemia with bilateral galactorrhoea and secondary amenorrhoea has a wide differential diagnosis and is not always caused by a prolactin secreting pituitary adenoma.

  • Significantly elevated serum oestradiol levels in the range seen in this case, in the absence of pregnancy, are indicative of an oestrogen-secreting tumour.

  • JGCTs are rare hormonally active ovarian neoplasms mostly secreting steroid hormones.

  • Serum inhibin can be used as a granulosa cell-specific tumour marker.

  • JGCTs have an excellent prognosis in the early stages of the disease.