Poorly differentiated pancreatic neuroendocrine carcinomas (NECs) are rare and aggressive malignancies with rapid disease progression and early widespread metastasis. Given histology similarity, they are commonly treated with platinum-based chemotherapy as small cell lung cancer (SCLC). However, no standard treatment has been established for recurrent or progressive disease. We present an Asian patient with recurrent poorly differentiated pancreatic NEC after curative surgery and adjuvant chemotherapy with cisplatin and etoposide. The tumor mutational burden (TMB) was high. The patient received chemotherapy combined with maintenance immunotherapy with nivolumab and achieved promising and durable response, suggesting TMB could be a biomarker to identify NEC patients for immune checkpoint inhibitor (ICI) treatment.

Immune checkpoint inhibitors (ICIs) are widely used in cancer therapy but can cause adverse events, including acute kidney injury (AKI). The incidence of ICI-associated AKI (ICI-AKI) varies across studies, and while steroids may aid in kidney recovery, their full effects require further investigation. Additionally, the risk of recurrent AKI with ICI rechallenge remains uncertain. This study assesses the incidence of ICI-AKI, evaluates steroid efficacy, and examines the risk of recurrent AKI after ICI-AKI. A comprehensive search of PubMed, Embase, and the Cochrane Library was conducted through May 2024. Outcomes included the incidence of ICI-AKI, kidney recovery after steroid therapy, and the risk of recurrent AKI with ICI rechallenge. A random-control model was used for analysis. This analysis included 16 studies involving 10,726 participants. The pooled incidence of ICI-AKI after following up for one year was 1.4% (95% CI 1.0-2.1%), with the incidence rate being 4.3 per 100 patient-years (95% CI 2.3-6.3 per 100 patient-years). ICI-AKI patients treated with steroid were more likely to achieve kidney recovery (OR 1.82, 95% CI 1.17-2.83, P = 0.008). No additional benefit was found from combining intravenous and oral steroids (OR 0.928, P = 0.863). The incidence of recurrent AKI after ICI-AKI was 18.0% (95% CI 13.2-23.9%). A substantial incidence of ICI-AKI of those receiving ICI was identified. Steroid treatment promotes kidney recovery, but adding intravenous steroids offers no additional benefit. There is an elevated risk of recurrent AKI with ICI rechallenge, underscoring the need for careful monitoring of kidney function.

Merkel cell carcinoma (MCC) is a rare primary neuroendocrine carcinoma (NEC) of the skin. As compared to pure MCCs, combined MCCs are aggressive and exhibit a higher probability of metastasis. A correct diagnosis might be missed, especially when the biopsy sample is too small or too superficial. We report a 79-year-old Taiwanese male who presented with lymphadenopathy suspicious for lymphoma. A nodal biopsy showed metastatic NEC. A skin tumor in the lower back was identified, and an incisional biopsy showed only squamous cell carcinoma (SCC). A subsequent excisional biopsy was performed based on the advice of the senior pathologist because of the presence of metastatic nodal NEC. Finally, a diagnosis of combined MCC and SCC was confirmed. Our literature review identified 13 cases of combined MCC with nodal metastasis as initial presentations, all with an aggressive clinical course. Both the MCC and non-MCC components could be present in the metastatic nodes. Metastases of pure MCC cells were observed in three combined MCCs in sun-protected areas, probably pointing to a distinct pathogenesis. Excision or punch biopsy to include the deep dermal NEC component is recommended as timely diagnosis is mandatory for appropriate management of patients with this rare skin cancer.