Primary peritoneal carcinoma: computed tomography and magnetic resonance findings

Mucinous carcinoma originating in the peritoneum diagnosed by an ascites cell block: a case report

BACKGROUND

Peritoneal carcinoma is a rare disease that is diagnosed and treated in a manner similar to ovarian cancer. In most cases, the histological type is serous carcinoma, and chemotherapy is effective. However, there are a few case reports of mucinous peritoneal carcinoma. We inferred the histological type before surgery using an ascites cell block sample, which was useful for determining the treatment plan.

CASE PRESENTATION

Our patient was a 60-year-old Japanese woman. She presented with a feeling of fullness in the abdomen. A computed tomographic scan showed a large quantity of ascitic fluid and thickening of the greater omentum, as well as thickening of the peritoneum at the pouch of Douglas and diaphragm. Hence, peritoneal carcinoma was suspected. The tumor markers carcinoembryonic antigen, cancer antigen 19-9, and cancer antigen 125 were all increased, and no malignant findings were observed in the uterus or ovaries. Cells suggestive of carcinoma were found in the ascitic fluid, and immunostaining by the cell block method suggested the possibility of mucinous carcinoma. The preoperative chemotherapy strategy was changed to short courses, and tumor reduction surgery was planned. Similar to the suspicion before surgery, the pathology results indicated mucinous carcinoma, and the therapeutic effect of chemotherapy was grade 0.

CONCLUSIONS

Determining whether peritoneal carcinoma is serous carcinoma is important for therapy and prognostic prediction. In this case, we encountered a patient for whom surgery was chosen because of drug therapy resistance inferred through histological type estimation using the cell block method. Inferring the histological type by cell block preparation is useful for diagnosis and treatment selection.

Multicenter Clinicopathological Study of High-Grade Serous Carcinoma Presenting as Primary Peritoneal Carcinoma

OBJECTIVE

We conducted a multicenter clinicopathological study to characterize patients with high-grade serous carcinoma presenting as primary peritoneal carcinoma (clinical PPC).

METHODS

At 9 sites in Japan, patients with clinical PPC diagnosed according to Gynecologic Oncology Group criteria were enrolled retrospectively. The Gynecologic Oncology Group criteria allow for minor ovarian involvement by high-grade serous carcinoma. There was no systematic detailed histopathological review of the fallopian tubes to determine whether they were involved by serous carcinoma.

RESULTS

There were 139 patients and 64% were aged 60 years or older. Median pretreatment serum CA-125 was 1653.5 IU/mL. Pretreatment performance status was poor in more than 50%, endometrial cytology was positive in 40.3%, and the preoperative clinical diagnosis was correct in 72.7%. Primary debulking surgery was performed in 36% of patients, whereas 64% underwent neoadjuvant chemotherapy (NAC) with interval debulking surgery (IDS). The main tumor sites were the upper abdomen (greater omentum), extrapelvic peritoneum, mesentery, and diaphragm. Lymph node metastasis was found in 46.8% of patients undergoing systematic retroperitoneal node dissection. The optimal surgery rate was 32.0% with primary debulking surgery versus 53.9% with NAC and IDS (P = 0.0139). The response rate was 82.0% with NAC and 80.6% with postoperative chemotherapy. Median progression-free survival was 19.0 months and median overall survival was 41.0 months. Multivariate analysis showed that prognostic factors for progression-free survival were NAC and residual tumor diameter after debulking surgery, whereas the only prognostic factor for overall survival was the residual tumor diameter.

CONCLUSIONS

This study identified various characteristics of clinical PPC. Neoadjuvant chemotherapy with IDS is a reasonable treatment strategy, and complete debulking surgery is optimum.

[Peritoneal AA amyloidosis simulating peritoneal carcinomatosis: a case report]

Amyloidosis is a group of deposition diseases that are classified according to the type of fibers accumulated and their characteristics. It can affect any organ. The clinical presentation depends on the organs and systems involved. We present the case of a patient with a history of Hashimoto's thyroiditis and systemic symptoms who presented with abdominal pain. Physical examination detected a palpable mass in the umbilical region. CT showed thickening of the wall of the colon with infiltration of the adjacent peritoneum and extension to the root of the mesentery with abundant ascites. The histological diagnosis was peritoneal AA amyloidosis.