Case Presentation: A 68-year-old female with hypertension and type 2 diabetes presented with diffuse abdominal pain for 2 weeks. Surgical history was remarkable for TAH & BSO. Family history was notable for colon cancer in her father. A physical exam showed abdominal distention, tenderness, and a palpable indurated periumbilical and right flank mass. Vitals were normal. Laboratory results were unremarkable. CT scan of the abdomen showed diffuse peritoneal carcinomatosis of unknown origin and abdominal pelvic ascites. CA-125 antigen was 4215 U/ml at admission. The patient underwent a CT-guided biopsy of the peritoneal mass which was positive for malignant cells consistent with mullerian origin with high-grade serous carcinoma. The neoplastic cells expressed CK7, PAX8, WT–1, CEA 125, and an aberrant p53 expression, with a PDL 1 TPS of 5%. The patient was discharged with oncology, gastroenterology, and PET/CT scan follow-ups. Colonoscopy and EGD excluded other primary sites. PET/CT scan showed extensive metastatic peritoneal disease with lesions in the liver and spleen and mediastinal lymph node enlargement. A diagnosis of primary peritoneal carcinoma was made based on histology and no other primary site. The patient was started on platinum-based neo-adjuvant chemotherapy and was planned for debulking surgery based on response to chemotherapy.
Discussion: PPC is a rare tumor mostly seen in women arising from the peritoneal lining and involving the omentum. Most patients are diagnosed at advanced stages of disease highlighting the aggressive nature of this malignancy necessitating prompt diagnosis and treatment [1].Clinical presentation includes non-specific symptoms such as abdominal pain and distension. BRCA 1 and 2 mutations are associated with an increased risk of PPC. Histologically, PPC is similar to epithelial ovarian cancer, with serous well-differentiated lesions, making diagnosis even more challenging [2]. In our case, the diagnosis was aided by a history of TAH and BSO. Potential gastrointestinal primary carcinomas were excluded with EGD and colonoscopy. CA-125 levels correlate with tumor burden and stage of disease in PPC, similar to ovarian cancer, with high levels correlating with a high burden of disease. Treatment modalities include cytoreductive surgery/ tumor debulking, and chemotherapy. The prognosis depends on tumor markers, the effectivity of primary debulking surgery, the stage of diagnosis, and the patient’s baseline functional status [1, 3].
Conclusions: PPC is a rare and aggressive tumor with a challenging diagnosis. Early diagnosis and prompt chemotherapy with cytoreductive surgery and close follow-up with Ca-125 levels and surveillance imaging are essential to improve survival in this rapidly progressive disease.
