Cytokeratin-20 negative nodal Merkel cell carcinoma with regressed primary: a potential pitfall in interpretation of nodal metastasis.

Merkel cell carcinoma (MCC) is a rare, highly aggressive cutaneous neuroendocrine carcinoma that affects sun-damaged skin. Histologically, the tumor consists of round cells with fine chromatin positive for cytokeratin 20 in ~90% of cases. Rare cases of MCC can regress spontaneously and present as nodal metastasis. Nodal MCC of unknown primary can cause a potential pitfall as they can be misinterpreted as other neuroendocrine carcinomas such as small cell carcinoma. We report a case of nodal MCC with an atypical immunohistochemistry pattern presented as bilateral axillary lymphadenopathy in a 90-year-old man with a remote history of a skin lesion that healed spontaneously leaving a scar.

The Texas Immuno-Oncology Biorepository, a statewide biospecimen collection and clinical informatics system to enable longitudinal tumor and immune profiling.

A detailed understanding of the molecular and immunological changes that occur longitudinally across tumors exposed to immune checkpoint inhibitors is a significant knowledge gap in oncology. To address this unmet need, we created a statewide biospecimen collection and clinical informatics system to enable longitudinal tumor and immune profiling and to enhance translational research. The Texas Immuno-Oncology Biorepository (TIOB) consents patients to collect, process, store, and analyze serial biospecimens of tissue, blood, urine, and stool from a diverse population of over 100,000 cancer patients treated each year across the Baylor Scott & White Health system. Here we sought to demonstrate that these samples were fit for purpose with regard to downstream multi-omic assays. Plasma, urine, peripheral blood mononuclear cells, and stool samples from 11 enrolled patients were collected from various cancer types. RNA isolated from extracellular vesicles derived from plasma and urine was sufficient for transcriptomics. Peripheral blood mononuclear cells demonstrated excellent yield and viability. Ten of 11 stool samples produced RNA quality to enable microbiome characterization. Sample acquisition and processing methods are known to impact sample quality and performance. We demonstrate that consistent acquisition methodology, sample preparation, and sample storage employed by the TIOB can produce high-quality specimens, suited for employment in a wide array of multi-omic platforms, enabling comprehensive immune and molecular profiling.

Pembrolizumab-Induced Immune-Mediated Glossitis.

Pembrolizumab (Keytruda), an anti-PD-1 antibody used in the treatment of several different malignancies has been identified to cause adverse effects pertaining to multiple body systems which include respiratory, gastrointestinal, dermatologic, and endocrine manifestations known as immune-related adverse events (IRAEs). Skin manifestations have been most described in current literature highlighting the most common adverse effects of this agent. However, adverse outcomes involving the oral mucosa have been rarely identified in the PD-1 and PD-L1 inhibitor classes of immunotherapeutic agents. We present a case of a 71-year-old male who was treated with a chemotherapeutic regimen including pembrolizumab for newly diagnosed squamous cell carcinoma of the lung, who later developed ulcerations on his tongue that were consistent with glossitis. Upon determining that this adverse effect may be immune-related, the patient was treated with oral prednisone 40 mg with a 10 mg taper each subsequent week, which resulted in significant improvement in the patient's symptoms following one month of treatment.