A case of thyrotropin-producing pituitary adenoma, accompanied by an increase in anti-thyrotropin receptor antibody after tumor resection

Clinical characteristics and outcomes of patients with TSH-secreting pituitary adenoma and Graves' disease - a case report and systematic review

BACKGROUND

Coexistence of TSH-secreting pituitary adenoma (TSHoma) and Graves' disease (GD) is rare and complicates the management decision.

METHODS

We present a case of the co-existence of TSHoma and GD. In addition, we systematically searched articles describing TSHoma and GD in the same patient published until 20th March 2023, using Pubmed, Scopus and Embase.

CASE PRESENTATION

A 46-year-old man presented with symptoms of thyrotoxicosis. His thyroid function tests showed serum TSH 3.35 (reference range 0.3-4.2) mIU/L, FT3 19.7 (3.7-6.4) pmol/L, and FT4 68.9 (11-23.3) pmol/L. The serum TSH receptor antibody was 11.5 mIU/L (positive at ≥ 1.75 mIU/L). Pituitary magnetic resonance imaging showed macroadenoma compressing the optic chiasm. The patient underwent trans-sphenoidal resection of pituitary adenoma. Postoperatively, he remained on maintenance carbimazole and octreotide.

RESULTS

Fourteen articles comprising 15 patients were identified from the systemic search. A total of 16 patients (including the current case) were included in the systematic review. The mean (± SD) age at diagnosis was 41 ± 13.6 years. The majority were females (75%). The median (IQR) TSH was 1.95 (0.12-5.5) mIU/L, the median (IQR) free T3 was 11.7 (7.6-19.7) pmol/L and the median (IQR) free T4 level was 47.6 (33.3-64.4) pmol/L. Ten (76.9%) patients had positive TSH receptor antibody levels. 84.6% had pituitary macroadenoma. Pituitary surgery was performed in 12 (75%) patients. At the last follow-up, 4 (25%) patients had complete resolution of symptoms after pituitary surgery, 3 (18.7%) were on maintenance treatment with thionamides for GD, 1 (6.25%) on beta-blockers and 1 (6.25%) on somatostatin analog.

CONCLUSION

TSHoma and GD can co-exist, and it is essential to identify this rare association as it can significantly impact treatment strategies.

A remarkable case of thyrotoxicosis initially caused by graves' disease followed by a probable TSHoma - a case report

BACKGROUND

Graves' disease is the commonest cause of thyrotoxicosis whilst thyrotropin (TSH)-producing pituitary adenomas (thyrotropinomas, TSHomas) are very rare and account for just 1-2% of all pituitary adenomas. Coexistence of a TSHoma and Graves' disease has been very rarely reported. Here, we report a case of a patient whose initial presentation with primary thyrotoxicosis due to Graves' disease, was subsequently followed by a relapse of thyrotoxicosis due to a probable TSHoma.

CASE

A sixty-eight year old woman was referred to our department with classical features of thyrotoxicosis. Initial biochemistry confirmed hyperthyroxinaemia [free thyroxine (fT4) 20.4 pmol/L (reference range 7.0-16.0)] and a suppressed TSH [< 0.02mIU/L (0.50-4.20)]. A technetium pertechnetate uptake scan was consistent with Graves' Disease. She was treated with carbimazole for 18 months and remained clinically and biochemically euthyroid. After stopping carbimazole her fT4 started to rise but TSH remained normal. Laboratory assay interference was excluded. A TRH stimulation test demonstrated a flat TSH response and pituitary MRI revealed a microadenoma. Remaining pituitary hormones were in the normal range other than a slightly raised IGF-1. An ¹¹C-methionine PET/CT scan coregistered with volumetric MRI (Met-PET-MRI^CR) demonstrated high tracer uptake in the left lateral sella region suggestive of a functioning adenoma. The patient declined surgery and was unable to tolerate cabergoline or octreotide. Thereafter, she has elected to pursue a conservative approach with periodic surveillance.

CONCLUSION

This is a very unusual case of thyrotoxicosis caused by two different processes occurring in the same patient. It highlights the importance of considering dual pathology when previously concordant thyroid function tests become discordant. It also highlights a potential role of Met-PET-MRI^CR in the localisation of functioning pituitary tumours.

THYROIDITIS DEVELOPING POST INITIATION OF OCTREOTIDE IN A CASE OF TSH SECRETING TUMOR

Thyroiditis developing post pituitary surgery in a case of TSH secreting tumor has been reported, albeit rarely. A 46 year old female was treated as a case of hypothyroidism for almost five years, however, TSH levels remained unsuppressed in spite of increasing thyroxine doses. A cyclic pattern of TSH with T3 secretion was observed after stopping thyroxine, though T4 levels were normal. T3 suppression test revealed a non suppressed TSH and MRI sella revealed a pituitary mass with Grade 1 cavernous sinus invasion. With a diagnosis of TSH secreting tumor, the patient was initiated on octreotide therapy. TFT normalized within 4 days of initiation of octreotide, tumor size reduced by about 30% within 2 months of therapy and goiter size reduced to almost half with octreotide therapy. Anti TPO levels which were initially negative became positive within a month of octreotide therapy and FNAC thyroid revealed thyroiditis. To the best of our knowledge, this is the second case report of development of thyroiditis after octreotide therapy. The immunomodulatory role of TSH and somatostatin may have a role in the development of thyroiditis in this case.

Concurrent Graves' Disease and TSH Secreting Pituitary Adenoma Presenting Suppressed Thyrotropin Levels: A Case Report and Review of the Literature

Background: Thyroid stimulating hormone (TSH) secreting pituitary adenoma (TSHoma) is a rare cause of hyperthyroidism. To date there have been only thirteen cases reporting the coexistence of TSHoma with Graves' disease (GD). The diagnosis and management for such hyperthyroidism due to both etiologies remain challenging. Case Report: A 55-year-old Chinese female presented with signs and symptoms of thyrotoxicosis. Thyroid function tests showed elevated thyroid hormones and mildly suppressed TSH values. Her anti-thyrotropin receptor antibody (TRAb) was positive. Octreotide suppression test successfully decreased her TSH. Magnetic resonance imaging showed a pituitary macroadenoma. She underwent endoscopic trans-sphenoidal resection and surgical pathology confirmed a TSH producing pituitary adenoma. Methimazole was prescribed after surgery and her clinical course was monitored. Conclusions: Here we report a case of a 55-year-old female with TSHoma and Graves' disease whose TSH level was mildly suppressed. This case emphasizes the importance of thoroughly evaluating the thyroid function test during the diagnosis of hyperthyroidism. It also highlights the challenges in the diagnosis and treatment of this rare condition.

DIAGNOSIS OF ENDOCRINE DISEASE: Diagnostic approach to TSH-producing pituitary adenoma

Thyrotropin (TSH)-secreting adenomas (TSHomas) are the rarest form of pituitary adenomas, and most endocrinologists will see few cases in a lifetime, if any. In most cases, the diagnostic approach is complicated and cases may be referred after being presented as a syndrome of inappropriate TSH secretion or as a pituitary mass. This review aims to cover the past, present and possible future diagnostic approaches to TSHomas, including different clinical presentations, laboratory assessment and imaging advances. The differential diagnoses will be discussed, as well as possible coexisting disorders. By evaluating the existing reports and reviews describing this rare condition, this review aims to present a clinically practical suggestion on the diagnosic workup for TSHomas, Major advances and scientific breakthroughs in the imaging area in recent years, facilitating diagnosis of TSHomas, support the belief that future progress within the imaging field will play an important role in providing methods for a more efficient diagnosis of this rare condition.

Coexistence of thyroid-stimulating hormone-secreting pituitary adenoma and graves' hyperthyroidism

BACKGROUND

Coexistence of thyroid-stimulating hormone (TSH)-secreting pituitary adenoma (TSHoma) with Graves' disease has been rarely reported. We describe a female patient displaying TSHoma with Graves' disease and who presented initially with inappropriate TSH values.

CASE REPORT

A 36-year-old woman presented with signs of thyrotoxicosis, small and vascular goiter and mild bilateral exophthalmos. Thyroid function tests showed hyperthyroxinemia and normal TSH values despite the use of different assays. Heterophile antibody testing result was negative. The patient underwent total right lobectomy with partial left lobectomy after 18 months of carbimazole treatment. Histology confirmed Graves' disease. Symptoms of thyrotoxicosis recurred 2 months later. Thyroid function tests showed hyperthyroxinemia and elevated TSH values. Investigations were consistent with a 10-mm TSHoma. The patient underwent a trans-sphenoidal tumor resection following preoperative lanreotide preparation. Histological examination and immunocytochemistry concluded to a pure TSH-producing tumor. There was no evidence of tumor recurrence after 18 years of follow-up.

CONCLUSION

Association of TSHoma with Graves' disease should be carefully taken into account, especially when TSH values are not compatible with either the clinical history or other thyroid functions tests.

A case of TSH-producing adenoma treated with octreotide in combination with thiamazole for the control of TSH and thyroid hormones after trans-sphenoidal neurosurgery

While TSH-producing adenoma (TSHoma) is rare, the diagnosis is often delayed because the clinical features are heterogeneous. The patient was a 69-year-old woman who had been referred to the Yachiyo Medical Center in August 2008, because of dyspnea, loss of appetite, weight loss of 10 kg, and diarrhea that lasted 4 years. We diagnosed this patient with pituitary TSH-producing macroadenoma. Thyroid hormone concentration was increasing although the serum TSH level was within a normal range after trans-sphenoidal surgery. We considered that because of enlargement of the thyroid gland due to long-term stimulation by TSH, a low concentration of TSH could stimulate the thyroid gland to produce excess T3 or T4. The somatostatin analogue, octreotide was used to control the TSHoma and serum TSH concentration but not thyroid hormone. The octreotide in combination with thiamazole treatment for 14 months controlled thyroid hormone concentration and decreased the thyroid mass, and ultimately, the thiamazole could be stopped. To date, the use of combination therapy of octreotide with thiamazole in patients with remaining TSH-producing adenoma without Basedow's disease is rare, and we suggest that this treatment is one of the therapeutic means to treat recurrence of TSH-producing adenoma after surgery with progressive complications or large thyroid gland.