Ectopic prolactin secretion secondary to an ovarian tumour

Summary Ectopic hormone secretion is a well-recognised phenomenon; however, ectopic prolactin secretion is exceptionally rare. Hoffman and colleagues reported the first ever well-documented case of ectopic prolactin secretion secondary to a gonadoblastoma. We report a lady who presented with galactorrhoea and a large ovarian tumour that was found to secrete high levels of prolactin. Learning points Aim of this case report is to highlight the occurrence of this condition. Lack of awareness can often lead to a diagnostic conundrum.


Background
We report this case to make clinicians aware of this rare condition (1) (2). Hoffman and colleagues reported the first ever well-documented case of ectopic prolactin secretion secondary to a gonadoblastoma (1).

Case presentation
A 27-year-old lady presented with 8-week history of hot flushes, headaches, galactorrhoea and delayed periods. She denied any problems with vision or fluctuation in weight. Her medical history was asthma and irritable bowel disease. She was an ex-smoker of 5 years with a two packs per year smoking history and drank alcohol occasionally. On examination, she was noted to have galactorrhoea on expression. She had normal visual fields tested by confrontation method. Systemic examination revealed a 10 cm supra-pubic mass on palpation.

Imaging
Magnetic resonance imaging of the pituitary was normal. Her computed tomography (CT) of the abdomen showed a right adnexal mass measuring 18!14!18 cm with retroperitoneal lymphadenopathy (Fig. 1).

Treatment
Therapy with cabergoline was initiated but discontinued due to intolerance. She was then started on bromocriptine 2.5 mg. She underwent right salpingo-oophorectomy with para-aortic node clearance. Three weeks postoperatively, her prolactin dropped to undetectable levels.

Outcome and follow-up
Post-operative histopathology, immunohistochemistry results under haematoxylin and eosin stain showed that the ovary was replaced by diffuse sheets of undifferentiated, highly atypical cells possessing enlarged nuclei. Tumour cells were positive for synaptophysin, p53 and epithelial membrane antigen (EMA), and showed negative expression for chromogranin, CK7, desmin, inhibin, melanA, PLAP and CD56. Following immunohistochemistry, the tumour was categorised as ovarian malignant small cell tumour of pulmonary type. Immunohistochemical staining for prolactin showed patchy but intense cytoplasmic, peri-nuclear dot-like positivity, which was reported to perhaps represent localisation of prolactin in Golgi complex (Fig. 3). This patient had adjuvant chemotherapy following her surgery. Her PET FDG scan performed 10 weeks postoperatively showed right oophorectomy, unremarkable upper abdominal viscera, clear lung fields and no evidence of mediastinal, abdominal or pelvic adenopathy. She had no disease recurrence on her 8-month follow-up scan. Her prolactin levels remained normal.

Discussion
Our case demonstrates ectopic prolactin secretion secondary to an ovarian malignant small cell tumour. Normalisation of prolactin levels soon after surgical removal of the tumour, positive immunohistochemistry for prolactin and normal pituitary gland on imaging strongly support the diagnosis. We report this case to highlight and make clinicians aware of this rare condition.

Declaration of interest
The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Funding
This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.    Patient consent Written informed consent was obtained from the patient/patient's mother for publication of this case report.
Author contribution statement Co-authors have contributed towards patient care, management and also towards writing and finalising the draft.