Small-cell Lung Carcinoma with Gastrointestinal Pseudo-obstruction as a Paraneoplastic Neurological Syndrome Elicited by an Immune Checkpoint Inhibitor

Abstract

Gastrointestinal pseudo-obstruction (GIPO) is a phenotype of the paraneoplastic neurological syndrome (PNS). We herein report a case of small-cell lung carcinoma (SCLC) with GIPO elicited by an immune checkpoint inhibitor (ICI). A 75-year-old man with SCLC developed intractable intestinal obstruction after receiving one course of anticancer drugs (durvalumab, etoposide, and carboplatin). The serum anti-Hu antibody (Hu-Ab) was positive, and the patient was diagnosed with GIPO. Corticosteroid treatment did not improve the GIPO, and the patient died. There are few reports of GIPO after ICI treatment in patients with lung cancer, so a further investigation will be required to elucidate the mechanism by which ICIs elicit PNS. Checking for neuronal antibodies may help identify patients with SCLC who are at risk of developing PNS due to ICI treatment.

Keywords: anti-Hu antibody; gastrointestinal pseudo-obstruction; immune checkpoint inhibitor; paraneoplastic neurological syndrome; small-cell lung carcinoma.

Figure 1.

Chest CT showing a right lower lobe mass that infiltrated the mediastinum and enlarged mediastinal and supraclavicular lymph nodes. CT: computed tomography

Figure 2.

Abdominal CT showing dilation of the large intestine. CT: computed tomography

Figure 3.

Chest CT showing shrinkage of the mass and lymph nodes. CT: computed tomography

Figure 4.

Lower gastrointestinal endoscopy revealed no evidence of obstruction, but localized erythema, erosions, and mild bleeding of the rectal mucosa were noted.

Figure 5.

Pathology of the rectal biopsy revealed a small number of apoptotic bodies (arrows) in some of the epithelium, but there were no malignant findings, crypt abscesses, or lymphocytic infiltration of the epithelium. HE: Hematoxylin and Eosin staining ×40