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Open access

W K M G Amarawardena, K D Liyanarachchi, J D C Newell-Price, R J M Ross, D Iacovazzo and M Debono

Summary

The granulation pattern of somatotroph adenomas is well known to be associated with differing clinical and biochemical characteristics, and it has been shown that sparsely granulated tumours respond poorly to commonly used somatostatin receptor ligands (SRLs). We report a challenging case of acromegaly with a sparsely granulated tumour resistant to multiple modalities of treatment, ultimately achieving biochemical control with pasireotide. A 26-year-old lady presented with classical features of acromegaly, which was confirmed by an oral glucose tolerance test. Insulin-like growth factor 1 (IGF1) was 1710 µg/L (103–310 µg/L) and mean growth hormone (GH) was >600 U/L. MRI scan showed a 4 cm pituitary macroadenoma with suprasellar extension and right-sided cavernous sinus invasion. She underwent trans-sphenoidal pituitary surgery. Histology displayed moderate amounts of sparsely granular eosinophilic cytoplasm, staining only for GH. Postoperative investigations showed uncontrolled disease (IGF1:1474 µg/L, mean GH:228 U/L) and residual tumour in the cavernous sinus. She received external beam fractionated radiation. Over the years, she received octreotide LAR (up to 30 mg), lanreotide (up to 120 mg) two weekly, cabergoline, pegvisomant and stereotactic radiosurgery to no avail. Only pegvisomant resulted in an element of disease control; however, this had to be stopped due to abnormal liver function tests. Fifteen years after the diagnosis, she was started on pasireotide 40 mg monthly. Within a month, her IGF1 dropped and has remained within the normal range (103–310 µg/L). Pasireotide has been well tolerated, and there has been significant clinical improvement. Somatostatin receptor subtyping revealed a positivity score of two for both sst5 and sst2a subtypes.

Learning points:

  • Age, size of the tumour, GH levels on presentation, histopathological type and the somatostatin receptor status of the tumour in acromegaly should be reviewed in patients who poorly respond to first-generation somatostatin receptor ligands.
  • Tumours that respond poorly to first-generation somatostatin receptor ligands, especially sparsely granulated somatotroph adenomas, can respond to pasireotide and treatment should be considered early in the management of resistant tumours.
  • Patients with membranous expression of sst5 are likely to be more responsive to pasireotide.
Open access

Ekaterina Manuylova, Laura M Calvi, Catherine Hastings, G Edward Vates, Mahlon D Johnson, William T Cave Jr and Ismat Shafiq

Summary

Co-secretion of growth hormone (GH) and prolactin (PRL) from a single pituitary adenoma is common. In fact, up to 25% of patients with acromegaly may have PRL co-secretion. The prevalence of acromegaly among patients with a newly diagnosed prolactinoma is unknown. Given the possibility of mixed GH and PRL co-secretion, the current recommendation is to obtain an insulin-like growth factor-1 (IGF-1) in patients with prolactinoma at the initial diagnosis. Long-term follow-up of IGF-1 is not routinely done. Here, we report two cases of well-controlled prolactinoma on dopamine agonists with the development of acromegaly 10–20 years after the initial diagnoses. In both patients, a mixed PRL/GH-cosecreting adenoma was confirmed on the pathology examination after transsphenoidal surgery (TSS). Therefore, periodic routine measurements of IGF-1 should be considered regardless of the duration and biochemical control of prolactinoma.

Learning points:

  • Acromegaly can develop in patients with well-controlled prolactinoma on dopamine agonists.
  • The interval between prolactinoma and acromegaly diagnoses can be several decades.
  • Periodic screening of patients with prolactinoma for growth hormone excess should be considered and can 
lead to an early diagnosis of acromegaly before the development of complications.
Open access

Maryam Rahman, Ignacio Jusué-Torres, Abdulrahman Alkabbani, Roberto Salvatori, Fausto J Rodríguez and Alfredo Quinones-Hinojosa

Summary

Pituitary adenomas are usually solitary lesions. Rarely, patients may present with two distinct pituitary tumors. We report a case of synchronous secretory pituitary adenomas in a woman who initially presented with elevated prolactin levels. She was initially treated with cabergoline, but, after many years, she began developing symptoms consistent with acromegaly. Imaging revealed two distinct tumors within the pituitary gland. Endocrinological investigation confirmed acromegaly. At the time of surgery, two separate tumors were identified and resected. Pathological analysis demonstrated one tumor as a prolactinoma, and the other tumor as a GH-secreting adenoma. Postoperatively, her GH and IGF1 levels normalized, while the prolactin level remained slightly above normal. This case highlights that GH and prolactin level elevation is not always from co-secretion by the same adenoma.

Learning points

  • Synchronous pituitary adenomas represent <0.5% of pituitary tumors requiring surgery.
  • In the setting of elevated GH and prolactin levels, one cannot assume that they are co-secreted by the same adenoma.
  • A careful study of hormonal workup and pre-operative imaging is necessary for synchronous pituitary adenomas to assure resection of both tumors.