Prolactin-Secreting Leiomyoma Causing Hyperprolactinaemia Unresponsive to Dopamine Agonist Therapy and Resolution following Myomectomy

Abstract

Prolactin-secreting leiomyomas are rare, with only eight cases reported in the literature. This case describes a 37-year-old female with hyperprolactinaemia (1846 mIU/L; 85–500 mIU/L) refractory to cabergoline causing infertility and galactorrhea. MRI pituitary was normal. The patient had a known enlarging uterine leiomyoma on serial pelvic ultrasounds (15.2 cm × 9.1 cm × 12.1 cm). The serum prolactin returned to subnormal levels two days postmyomectomy and showed recovery to normal levels in the months following surgery. Immunostaining of the leiomyoma for prolactin was negative. Despite not staining for prolactin, quick resolution of the patient’s hyperprolactinaemia after myomectomy supports the diagnosis of a prolactin-secreting fibroid. A prolactin-secreting leiomyoma should be considered in patients with hyperprolactinaemia and normal pituitary MRI which is refractory to dopamine receptor agonist therapy who also have evidence of a uterine fibroid. In patients wishing to seek fertility, myomectomy should be considered to allow for normal ovulation and possibility of future fertility.

The effects of prolactin receptor blockade in a murine endometriosis interna model

“…It remains to be established whether systemic hyperprolactinemia seen in a subgroup of endometriosis patients is always due to increased pituitary prolactin production or in some cases also due to local prolactin production in the endometriotic lesions. D2R agonists in contrast to PRLR antibodies would not be effective in the latter scenario as already demonstrated in prolactin‐producing leiomyoma patients 27,28 …”

“…There are several case‐reports describing women suffering from prolactin‐producing leiomyomas leading to systemic hyperprolactinemia which was treatment‐refractory to D2R agonists 27,28 . Myomectomy but not D2R agonist treatment led to normalization of prolactin levels 27,28 thus proving the inability of D2R agonists to inhibit extra‐pituitary prolactin synthesis.…”

“…There are several case-reports describing women suffering from prolactin-producing leiomyomas leading to systemic hyperprolactinemia which was treatment-refractory to D2R agonists. 27,28 Myomectomy but not D2R agonist treatment led to normalization of prolactin levels 27,28 thus proving the inability of D2R agonists to inhibit extra-pituitary prolactin synthesis. It remains to be established whether systemic hyperprolactinemia seen in a subgroup of endometriosis patients is always due to increased pituitary prolactin production or in some cases also due to local prolactin production in the endometriotic lesions.…”

“…D2R agonists in contrast to PRLR antibodies would not be effective in the latter scenario as already demonstrated in prolactin-producing leiomyoma patients. 27,28 For feasibility reasons and to reduce the injection burden for the animals, bromocriptine was only administered on 5 days and not 7 days per week. Therefore, insufficient dosing could explain its reduced efficacy in experiment 2 when compared with the effects of the PRLR antibodies at a dose of 30 mg/kg.…”

Prolactinoma or leiomyoma-associated hyperprolactinemia—this is the question, a case report and review of the literature

“…Moreover, ectopic intracranial prolactinomas originating from pharyngeal pituitary remnants as well as ectopic prolactin production by mesenchymal and other tumours have been described in the literature since 1970ies [3][4][5][6][7][8]. Leiomyoma-associated hyperprolactinemia has also been reported, though contradictory results have been obtained by immunostaining for prolactin in fibroid tissues [9,10]. Nevertheless, the rapid normalization of prolactin after myomectomy in patients with intact pituitary supports the diagnosis [9,10].…”