Diagnostic Complexity of a Sparsely Granulated Adrenocorticotropic Hormone-Secreting Pituitary Tumor in a Young Female Without Cushing’s

Sparsely granulated corticotroph pituitary neuroendocrine tumors are rare tumors that may sometimes present without signs of hypercortisolemia, creating diagnostic challenges. We describe a case of a 29-year-old female who sought medical attention due to amenorrhea. Diagnostic evaluations revealed hyperprolactinemia, and an MRI showed a 1.2 x 1.5 x 1.6 cm pituitary macroadenoma, which caused a mass effect on the optic chiasm. The patient subsequently had transsphenoidal endoscopic resection. Histological examination confirmed the presence of a sparsely granulated corticotroph pituitary neuroendocrine tumor with minimal ACTH reactivity. Despite having high serum cortisol and ACTH levels, the patient had minimal clinical signs of Cushing’s disease. This case demonstrates the challenges in diagnosing sparsely granulated corticotroph pituitary adenomas. Without proper identification and management, these tumors can cause significant complications.