Prolactinoma is the most common secreting pituitary tumor, accounting for nearly 40% of pituitary adenomas [1] . It primarily manifests in women of childbearing age through hyperprolactinemia, which is responsible for amenorrhea, galactorrhea, or infertility [2] [3] . During pregnancy and the postpartum period, prolactin plays a major physiological role in lactogenesis and the maintenance of lactation [4] . However, in cases of active prolactinoma, milk production can become excessive and pathological, leading to unusual local complications. Postpartum hyperlactation (or “oversupply syndrome”) is an often underestimated condition, defined by milk production significantly exceeding the infant’s needs. Hyperlactation, defined as a daily milk production exceeding 1.5 liters (approximately >1500 mL/day) or persistent milk leakage beyond normal physiologic levels, was used as the diagnostic criterion in this study. Clinically, hyperlactation (also called galactorrhea due to overproduction) is generally considered when: milk output >1.5 L/day in established lactation, or engorgement and leakage causing discomfort not attributable to normal early postpartum physiology [5] [6] . It promotes milk stasis, painful engorgements, and eventually bacterial superinfection, which can progress to recurrent mastitis or breast abscesses [7] [8] . Endocrine causes of this condition remain exceptional in the literature, with only a few cases of prolactinomas leading to pathological hyperlactation having been described [9] - [11] . Cabergoline, a dopaminergic agonist, is the standard treatment for prolactinomas, allowing for rapid normalization of prolactin levels and tumor regression [12] . However, its use in the postpartum period should be cautious due to its inhibitory effect on lactation and potential long-term side effects [13] [14] . We report here a rare case of recurrent postpartum breast engorgements and abscesses complicating hyperlactation due to an unrecognized prolactinoma, to draw attention to this little-known endocrine cause of pathological hyperlactation and recurrent breast infections.

We report the case of a 34-year-old patient, G2P2002, with no notable medical history. Her first delivery was at term and complication-free, followed by normal exclusive breastfeeding for six months. During her second pregnancy, her milk production started late, on the third day postpartum. Ten days postpartum, the patient noted excessive milk production, significantly greater than what she experienced during her first pregnancy. This hyperlactation caused repeated breast engorgement despite attempts to manually express milk using “traditional methods,” and resulted in cracked nipples. Breastfeeding became painful and uncomfortable for both the mother (breast tension, pain) and the newborn, who was hindered by an overly abundant milk flow that made suction difficult.

During the first month of breastfeeding, the patient noticed a decrease in the infant’s appetite and the appearance of white deposits on the tongue and oral mucosa (thrush). The diagnosis of neonatal oral candidiasis was made during a pediatric consultation and treated effectively, with the complete disappearance of lesions. Three months postpartum, the patient experienced sharp pain in her right breast. Despite hot water massages, relief was temporary. The breast was tense, heavy, warm, and painful, with a sensation of electric shocks. After breastfeeding, it became engorged again in less than 20 minutes, necessitating frequent use of a breast pump for decongestion. The overproduction of milk caused the infant to choke during feedings. Repeated use of the breast pump, without significant improvement, led to chronic breast overdistension, causing intense inflammation, fever, and persistent pain. The patient sought emergency care due to purulent discharge from the right breast, despite the healing of the nipple cracks.

Upon admission, she had a fever of 39˚C, distended and asymmetrical breasts, painful on palpation, with erythematous areas and purulent discharge on expression. Given the excessive milk production and recurring engorgements, a serum prolactin level was requested, revealing hyperprolactinemia at 358 ng/mL. The patient was referred for an endocrinology consultation. Pituitary MRI revealed a pituitary microadenoma ( Figure 1 & Figure 2 ).

The management involved the immediate suppression of lactation and cessation of breastfeeding. Treatment with cabergoline 0.5 mg per week for two months was initiated, along with surgical drainage of the abscesses, local care (washing with saline solution, betadine dressing twice daily). Abcess fluid cultures were performed and revealed the presence of Staphylococcus aureus. The antibiotic susceptibility testing showed resistance to amoxicillin-clavulanic acid and sensitivity to lincomycin and clindamycin. Treatment was initiated with lincomycin at a dosage of 500 mg every 12 hours for a duration of 10 days.

The evolution was favorable: milk secretion gradually decreased, the breast suppuration disappeared, and the signs of infection regressed. However, the patient subsequently experienced diffuse alopecia ( Figure 3 ), prompting the early discontinuation of cabergoline after one month of treatment and she was referred for a dermatological evaluation.

The reported case illustrates a rare form of postpartum hyperlactation secondary to a prolactinoma, complicated by iterative engorgements and breast abscesses. This presentation is exceptional: the literature reports fewer than ten similar cases described in the past twenty years [1] [2] .

This case report highlights the critical link between chronic hyperprolactinemia, even when masked by the physiological state of puerperium, and severe, recurrent breast pathology. Hyperlactation and subsequent recurrent breast abscesses in the post-partum period represent an often-recognized presentation of an underlying endocrine disorder, such as prolactinoma. The primary clinical implication of this case is that recurrent or unusually severe mastitis/abscesses during lactation should not solely be managed as a routine infectious process. Clinicians, including obstetricians, pediatricians, and general practitioners, must maintain a high index of suspicion for systemic causes when standard treatments fail or symptoms are atypical. Measuring serum prolactin levels should be considered in the workup of patients with intractable hyperlactation or recurrent breast infections.

Informed consent was obtained from the patient for the publication of this case report and the associated images. However, she did not authorize the publication of images showing the breast abscesses. Anonymity was maintained in accordance with the ethical principles of the Declaration of Helsinki. No identifying information about the patient has been disclosed in this article.