Hyaline-vascular type unicentric Castleman disease with dysplastic follicular dendritic cell proliferative lesions: a case report.

Castleman disease (CD) is a rare lymphoproliferative disease. Hyaline-vascular type unicentric CD has a good prognosis if completely resected during surgery. However, follicular dendritic cell proliferative lesions have the potential for recurrence and metastasis. A 22-year-old man was referred to our hospital with the chief complaint of nausea and vomiting. These symptoms were caused by a right mesocolonic tumor pushing the duodenum. The patient underwent laparoscopic tumorectomy and complete surgical excision. The postoperative course was uneventful, with no complications. Pathological examination confirmed that the tumor was an enlarged lymph node, typical of hyaline vascular-type CD; however, follicular dendritic cell proliferative lesions were noted. We report a rare case of hyaline-vascular-type CD with follicular dendritic cell proliferative lesions associated with malignancy, as limited case reports exist on this particular disease.

Successful Multidisciplinary Treatment with Laparoscopic Hepatectomy and Adjuvant Therapy for Metachronous Solitary Hepatic Metastasis after Excision of a Primary Anorectal Malignant Melanoma: A Case Report.

Anorectal malignant melanoma (ARMM) is extremely rare and generally lethal, irrespective of the treatment administered. The disease is often diagnosed late, metastases being present in approximately two-thirds of patients at the time of initial diagnosis. Solitary metastasis of ARMM to a distant organ is exceedingly rare. A 76-year-old woman with a history of laparoscopic abdominoperineal resection of an ARMM 13 months previously, was found to have a solitary liver metastasis in the follow-up computed tomography. A preoperative work-up showed no other distant metastases nor contraindication to surgery. It was therefore considered that resection was indicated. The metachronous solitary liver metastasis from an ARMM was treated by laparoscopic wedge hepatectomy of the eighth segment 18 months after excision of her primary ARMM. Adjuvant therapy with pembrolizumab was initiated and continued at 6-week intervals. The patient has not exhibited any immune related Adverse Effects (irAE) during or subsequent to treatment with pembrolizmab and has now completed 12 months of adjuvant pembrolizumab therapy, having survived 33 months from the initial operation for primary ARMM, and remaining recurrence-free 14 months after hepatectomy. ARMM is extremely rare and resection of a metachronous solitary metastasis followed by adjuvant therapy has not previously been reported. We hope this case will be useful for clinicians who might treat similar patients.

Peritoneal Recurrence of Cecal Cancer with Specific Imaging Findings and Shrinkage after Treatment with Pembrolizumab.

Pembrolizumab is one of the treatment options for treatment-refractory unresectable advanced or metastatic colorectal cancer with microsatellite instability-high (MSI-H) or deficiencies in DNA mismatch repair (dMMR). Herein, we report a case in which a recurrent cecal cancer lesion showed specific imaging findings and local inflammatory findings during treatment with pembrolizumab, followed by marked shrinkage. The patient was an 80-year-old woman. Postoperative peritoneal recurrence of cecal cancer of approximately 7 cm in size was observed. The patient had MSI-H and was treated with pembrolizumab. After five courses of treatment, the patient presented to our hospital with a chief complaint of abdominal pain. A blood test showed a strong inflammatory reaction, and computed tomography (CT) showed diffuse low-density area in the tumor. Under the suspicion of an abscess, conservative treatment was initiated and the patient quickly recovered. A CT at 1 month showed a marked reduction in size at the same site, and a CT at 3 months showed that the recurrent foci had almost disappeared. The inflammatory reaction before shrinkage in this case may have been caused by tumor immune response to pembrolizumab.