Ectopic prolactin secretion from a perivascular epithelioid cell tumor (PEComa)

J Clin Endocrinol Metab. 2014 Nov;99(11):3960-4. doi: 10.1210/jc.2014-2623. Epub 2014 Aug 15.


Background: The diagnosis of ectopic pituitary hormone secretion requires abnormally high circulating hormone levels, absence of a pituitary tumor, and localization of the hormone in question to the extrapituitary malignant neoplasm. No case of a malignant solid tumor producing prolactin has been documented thus far.

Case report: A 47-year-old woman presented with amenorrhea and galactorrhea of 3-year duration. Serum prolactin ranged from 300 to > 900 ng/mL, and other pituitary and thyroid indices were normal, including testing for macroprolactinemia. Pituitary magnetic resonance imaging revealed a partially empty sella but no tumor. Cabergoline 0.5 mg twice weekly did not affect her prolactinemia (1700 to 1900 ng/mL), and the medication was stopped. In the meantime, she developed abdominal pain, and a computed tomography scan showed a 17 × 13 × 8-cm mass abutting the distal stomach, proximal duodenum, and right colon. After the tumor was excised, her galactorrhea resolved, menstrual periodicity resumed within the first month, and serum prolactin fell to 5 ng/mL. Pathological examination of the excised tumor was consistent with perivascular epithelioid cell tumor. Between 5 and 10% of the tumor cells were strongly positive for prolactin on immunohistochemistry. RT-PCR detected prolactin mRNA in the tumor cell extract, confirming the diagnosis of ectopic prolactin synthesis and secretion.

Conclusion: We present the first example of massive and symptomatic hyperprolactinemia due to ectopic prolactin production by a solid extrapituitary mesenchymal tumor confirmed with both mRNA analysis and immunohistochemistry. Ectopic prolactin secretion should be suspected in patients with a prolactin >200 ng/mL and negative sellar MRI.

Publication types

  • Clinical Conference

MeSH terms

  • Female
  • Gastrointestinal Neoplasms / complications
  • Gastrointestinal Neoplasms / metabolism*
  • Gastrointestinal Neoplasms / pathology
  • Humans
  • Hyperprolactinemia / etiology*
  • Hyperprolactinemia / pathology
  • Middle Aged
  • Perivascular Epithelioid Cell Neoplasms / complications
  • Perivascular Epithelioid Cell Neoplasms / metabolism*
  • Perivascular Epithelioid Cell Neoplasms / pathology
  • Prolactin / metabolism*


  • Prolactin