Rituximab-induced Crohn's disease.

The use of rituximab has significantly improved outcomes in patients with haematological malignancies and autoimmune disease. There are reports of rituximab-associated ulcerative colitis; however, we report for the first time, two cases of rituximab-induced Crohn's disease in elderly patients treated for lymphoma. Both patients had evidence of inflammation, ulceration, and granulomas consistent with Crohn's disease, and responded well to immunosuppression. The association of rituximab and ileocolitis suggests a protective effect of CD20 + lymphocytes in the gut, and implicates their depletion to the development and exacerbation of inflammatory bowel disease.

A rare case of MRI of myxoid hepatocellular adenoma with gadoxetic acid uptake.

This is the first case report of 43-year-old lady with a myxoid hepatic adenoma which demonstrated significant contrast uptake during hepatobiliary phase imaging. This highlights the potential for a missed diagnosis and likely subsequent malignant transformation in a young patient in whom it was initially presumed to be focal nodular hyperplasia with no further surveillance.

ALK-rearranged renal cell carcinoma with TPM3::ALK gene fusion and review of the literature.

ALK-rearranged renal cell carcinoma (ALK-RCC) is a very rare novel molecularly defined entity in the recently published fifth edition of the World Health Organization classification of tumours. We describe a case of ALK-RCC in a 76-year-old female. The tumour was composed of discohesive rhabdoid cells and pleomorphic, multinucleated cells (equivalent to ISUP/WHO grade 4). The tumour showed expression with PAX8, Keratin 7 and alpha methylacyl CoA racemase. ALK (D5F3 clone) was strongly and diffusely positive. ALK-FISH showed significant split signals of ALK, confirming the diagnosis. RNA sequencing showed TPM3::ALK rearrangement. Including the current case, there are 14 reported ALK-RCC cases with the same TPM3 fusion partner gene. Review of these published cases highlights their morphological heterogeneity and stresses the importance of running ALK immunohistochemistry on difficult cases to classify renal tumours. This is important while identification of ALK-RCC has clinical significance due to the availability of targeted therapy with ALK inhibitors.

Very Delayed Acute Hepatitis after Pembrolizumab Therapy for Advanced Malignancy: How Long Should We Watch?

Immune checkpoint inhibitors (ICIs) have led to major therapeutic advances in the management of malignancy. Despite promising outcomes for some cancers, ICIs are linked to unique side-effects known as immune-related adverse events (IrAEs). These may affect a wide array of organ systems. In particular, ICI-induced hepatitis is diagnostically challenging given its variable natural history and clinical manifestations. The onset of ICI-induced hepatitis often occurs between 6 and 14 weeks after treatment initiation and rarely exhibits delayed presentations or manifests after treatment cessation. We present a case of very delayed-onset ICI-induced hepatitis, stressing the importance of long-term surveillance for immune-indued hepatitis in patients initiated on ICIs even long after treatment cessation.