Peritoneal implantation of pheochromocytoma – pheochromocytomatosis. A case report and mini review

Erik Bényei¹András Laki¹Gergely Kiss²Zsolt Varga³Miklós Tóth^1*Judit Tőke¹

• ¹Department of Internal Medicine and Oncology, Semmelweis University, Budapest, Hungary
• ²Medical Imaging Centre, Semmelweis University, Budapest, Hungary
• ³Medical Imaging Centre, Department of Nuclear Imaging, Budapest, Hungary

Introduction: Pheochromocytomatosis, defined as the implantation of pheochromocytoma cells to the intraoperatively opened surfaces during surgical manipulation, is an infrequent complication of surgical intervention of pheochromocytomas. Only a handful of pheochromocytomatosis cases have been reported since the first case was described in 2001. Case report: In 2011, a 33-year-old male patient presented with episodic palpitations and hypertensive surges triggered by physical activity. Imaging revealed a left adrenal tumour, which showed intense radiopharmaceutical uptake on 131I-metaiodobenzylguanidine ([131I]MIBG) scintigraphy. Urinary analysis of metanephrines confirmed pheochromocytoma, and laparoscopic left-sided adrenalectomy was performed. Owing to the large tumour size, intraoperative fragmentation was necessary for removal. The patient remained asymptomatic for five years. In 2016, recurrent paroxysmal symptoms prompted imaging, revealing a lesion at the left renal hilum. During the reoperation in 2017, multiple peritoneal tumour deposits were observed and later confirmed histologically. Over the following years, the patient received conservative, symptomatic treatment with tolerable paroxysmal symptoms. In 2023, worsening symptoms led to the decision to commence three cycles of ([131I]MIBG) therapy, followed by alleviation of symptoms, and a decrease in biochemical parameters. Discussion: An extensive literature search for publications from the past 25 years identified 22 pheochromocytomatosis cases whose details were also summarised and analysed. This condition appears to have a longer recurrence-free survival compared to patients' cohorts with metastatic pheochromocytomas. Pheochromocytomatosis is usually characterised by a prolonged asymptomatic postsurgical interval, emphasising the need for long-term follow-up with close biochemical and radiological surveillance. Treatment strategies parallel those used for advanced/metastatic pheochromocytomas.