褐色細胞腫の非定型的なプレゼンテーションと原因不明の持続熱：症例報告

Pheochromocytoma is a rare neuroendocrine tumor classically associated with episodic adrenergic symptoms and hypertension, but its clinical presentation is highly variable and may be misleading. Fever is an uncommon manifestation and is rarely the dominant presenting feature, which can result in diagnostic delay and extensive evaluation for infectious, inflammatory, or malignant causes. We report the case of a middle-aged woman who presented with prolonged fever, weight loss, and systemic inflammatory features without hypertension or classic catecholamine-related symptoms. Extensive investigations for infectious, autoimmune, and malignant etiologies were unrevealing. Cross-sectional imaging incidentally identified a right adrenal mass, which on further evaluation demonstrated imaging and biochemical features consistent with pheochromocytoma. Functional imaging supported the diagnosis and excluded disseminated disease. The patient underwent appropriate preoperative medical preparation followed by laparoscopic adrenalectomy, with rapid postoperative resolution of fever and inflammatory markers and sustained clinical recovery on follow-up. This case highlights an unusual inflammatory presentation of pheochromocytoma and emphasizes the importance of maintaining a broad differential diagnosis in patients with fever of unknown origin. Endocrine tumors should be considered in the evaluation of persistent unexplained fever, particularly when an adrenal lesion is identified, even in the absence of classic hormonal symptoms. Early recognition is essential, as timely surgical intervention is curative and prevents potentially life-threatening complications associated with undiagnosed pheochromocytoma.