Introduction: Brown tumors are rare skeletal manifestations of primary hyperparathyroidism (PHPT), now seen in less than 5% of cases due to widely accessible biochemical screening. Despite being benign, they can mimic malignant bone lesions, making diagnosis challenging. Case: A 45-year-old female presented with lethargy and hypercalcemia (corrected calcium 3.5 mmol/L) and was discharged after intravenous zoledronate. She returned 1 week later with an enlarging gingival mass present for 2 months but not previously disclosed, with a strong family history of malignancy. Examination revealed a 6 × 3 cm pedunculated lesion over the right alveolar ridge. Biochemistry showed persistent hypercalcemia (2.7–2.9 mmol/L), hypophosphatemia, and elevated alkaline phosphatase. Contrast-enhanced computed tomography of the neck demonstrated lytic mandibular and skull changes, raising suspicion for malignancy. Tumor markers and multiple myeloma screening were negative. Parathyroid hormone (PTH) later returned markedly elevated at 222.1 pg/mL (upper limit of normal 56.9 pg/mL), consistent with PHPT, alongside concomitant vitamin D deficiency. Excision biopsy of the mandibular lesion confirmed a brown tumor on histopathology. Following preoperative localization, she underwent left parathyroidectomy and recovered without hungry bone syndrome. Histology confirmed a parathyroid adenoma, and she has remained normocalcemic since. Brown tumors arise from prolonged osteoclastic activity and represent advanced PHPT. Craniofacial involvement is rare, with the mandible affected in 4–5% of cases, and lesions may clinically and radiologically mimic primary bone tumors or metastases, creating diagnostic uncertainty. Hypercalcemia should be systematically investigated to determine the underlying cause, with early measurement of PTH to distinguish PTH-dependent from PTH-independent etiologies. Untreated brown tumors may result in bone pain, deformity, pathological fractures, and functional impairment, highlighting the importance of early detection and management. Conclusion Brown tumors, although rare, remain an important differential diagnosis for lytic bone lesions in the context of hypercalcemia. Early measurement of PTH and careful clinical examination are essential to avoid misdiagnosis and prevent disease-related morbidity.
Neoplasms

Introduction: Pituitary macroadenomas may present with mass effects, hypopituitarism, or hormone hypersecretion. Hyperprolactinemia, resulting from a prolactin-secreting tumor or stalk compression, typically suppresses gonadotropins. Thus, elevated follicle-stimulating hormone (FSH) and luteinizing hormone (LH) with low testosterone in this context are unusual. We report a macroprolactinoma with a clinically non-functioning gonadotroph adenoma. Case: A 69-year-old male presented with acute giddiness and headache while in Vietnam. He reported reduced libido but no visual symptoms or galactorrhea. Examination showed no neurological deficits, normal visual fields, and secondary sexual characteristics; bilateral testes volume of 25 mL. Magnetic resonance imaging (MRI) brain revealed a 1.6 × 2.2 × 2.1 cm pituitary macroadenoma compressing the optic chiasm and pituitary stalk. Initial pituitary evaluation demonstrated hyperprolactinemia (prolactin >200 µg/L; normal 2.4–13.1), central hypothyroidism (T4 6.8 pmol/L [7.8–14.4], thyroid-stimulating hormone 2.3 mIU/L [0.38–5.3]), elevated FSH (21.5 IU/L [1.2–19.2]) and LH (191 IU/L [1.24–8.62]), low testosterone (8.88 nmol/L), normal insulin-like growth factor 1 (IGF-1) (68 µg/L [46.5–191.9]), and cortisol 237 nmol/L. Cabergoline was initiated at 0.25 mg twice weekly and titrated to 1 mg twice weekly over 4 months, alongside levothyroxine 25 µg daily. Repeated MRI brain 2 months after cabergoline initiation showed a persistent macroadenoma (1.7 × 2.2 × 2.2 cm) with bilateral cavernous sinus extension. Prolactin decreased to <170 µg/L, central hypothyroidism persisted; levothyroxine was optimized, and hydrocortisone was initiated. At the 5-month follow-up, prolactin further improved to 57 µg/L. Central hypothyroidism and borderline adrenal function persisted, requiring continued replacement therapy. Testosterone remained low-normal (10.2 nmol/L) despite elevated FSH (15.4 IU/L) and LH (92 IU/L). Followup MRI and hormonal reassessment were planned in May 2026. Conclusion Profoundly elevated prolactin level >200 µg/L and response to cabergoline reflect true prolactinoma rather than stalk effect. Persistently low testosterone with discordant high FSH/LH suggests a non-functioning gonadotroph component producing biologically inactive gonadotropins. Definitive diagnosis requires histopathological confirmation, while serial biochemical and radiological follow-up guides management and clarifies tumor subtype.
Gonadotrophs ; Hyperprolactinemia