Colonic mucosal pseudolipomatosis: Are we aware of it?

Colonic Pseudolipomatosis: A Rare but Characteristic Endoscopic Condition

BACKGROUND Colonic pseudolipomatosis (CP) can pose a diagnostic challenge due to its rare incidence and multiple presentations, most of them not very familiar to the endoscopist. Its etiology and pathogenesis have not been completely clarified. It can be related to mucosal iatrogenic injury caused during endoscopic examination or to chemical injury caused by residual disinfectants on the surface of the scope after cleansing. Imaging tests such as CT or MRI do not contribute to the diagnosis, but this condition has characteristic features that must be differentiated from pre-malignant lesions, like lateral-spreading tumors, in order to avoid further investigation and unnecessary treatment, such as endoscopic mucosal resection. CASE REPORT We report a case of a 65-year-old man who underwent to a screening colonoscopy due to his strong family history of colorectal cancer. Confluent whitish laterally-spreading lesions with a round pit-pattern in white-light HD scope were identified in the cecum and ascending colon. The lesion was biopsied with a cold forceps. Histopathologic analysis revealed multiples cysts filled with gas within the mucosal layer, associated with a mild inflammatory process, mainly composed of mononuclear cells and eosinophils. No giant multinuclear cells were identified. Moreover, although there was a mild inflammatory process in the epithelium, the architectural organization and tissue maturation were preserved with no nuclear atypia, consistent with a diagnosis of colonic pseudolipomatosis. CONCLUSIONS Colonic pseudolipomatosis is a rare, benign condition that must be not mistaken for more serious conditions, as CP requires no further investigation or treatment. In this setting, proper diagnosis is key to avoid unnecessary procedures.

A case of immune checkpoint inhibitor-related colitis with a distinctive endoscopic finding of colonic pseudolipomatosis

A man in his 70s received anticancer chemotherapy with the anti-programmed cell death protein-ligand 1 antibody atezolizumab for non-small cell lung cancer. Ten days later, he developed diarrhea and skin rash, which were suspected to be due to immune-related adverse events, and was treated with prednisolone for 2 weeks. Five weeks after atezolizumab administration, he was admitted to our hospital for Common Terminology Criteria for Adverse Events Grade 3 diarrhea and hematochezia. Sigmoidoscopy revealed a dark red color in the mucosa of the transverse colon and multiple whitish mucosal plaques extending from the transverse colon to the rectum. Biopsy specimens revealed empty vacuoles in the lamina propria with infiltration of numerous inflammatory cells, including CD8⁺ T cells. Based on the findings of sigmoidoscopy and histology, the diagnosis was immune checkpoint inhibitor-related colitis with colonic pseudolipomatosis. The endoscopic findings and symptoms were markedly improved by prednisolone administration. We herein report the first case of immune checkpoint inhibitor-related colitis with characteristic endoscopic findings of colonic pseudolipomatosis. It is important to perform endoscopy and histological evaluation to determine the differential diagnosis and treatment strategy for patients treated with immune checkpoint inhibitors.

Unusual mucosal lesion: A case of rectal pseudolipomatosis in a 60-year-old patient

Pseudolipomatosis is a very rare benign pathologic condition of colorectal mucosa. It is caused by the presence of gas bubbles in the intestinal mucosa. The endoscopic and histologic aspects are misleading as they suggest adipocytic or vascular lesions. We present herein a case of rectal pseudolipomatosis in a 60-year-old woman presenting with rectal bleeding. The endoscopic pattern was not suggestive of the lesion, and the histopathologic analysis of the patient’s rectal biopsies revealed characteristic features of pseudolipomatosis. Rectocolic pseudolipomatosis is a very rare benign condition with challenging clinicopathologic presentation. Clinicians and pathologists should be aware of this uncommon lesion for correct diagnosis and appropriate clinical management.

Pseudolipomatosis of the Colon and Cecum Followed by Pneumatosis Intestinalis

A 74-year-old Japanese woman was diagnosed with pseudolipomatosis of the cecum and ascending colon. Colonoscopy was performed, which revealed the presence of slightly elevated white lesions, while a magnifying observation showed microbubbles within the mucosa. A month after colonoscopy, the patient was diagnosed with pneumatosis intestinalis. Although the exact pathogenesis is unclear, pneumatosis intestinalis may arise secondary to pseudolipomatosis. This case also indicates that a magnifying observation during colonoscopy may aid in the diagnosis of pseudolipomatosis of the large intestine, since it shows microbubbles within the mucosa, which may be a distinctive feature reflecting the pathology of this disease.