Paraneoplastic limbic encephalitis associated with mixed olfactory neuroblastoma and craniopharyngioma: A case report and literature review

Abstract

Rationale: Paraneoplastic limbic encephalitis (PLE) is a rare disorder of the nervous system associated with malignant disease. It has a subacute onset with the following symptoms: cognitive dysfunction, seizures, irritability, hallucinations, and short-term memory loss. Herein, we report the case of a 35-year-old man with PLE, an olfactory neuroblastoma (ONB) admixed with craniopharyngioma, and serum anti-Hu antibodies.

Patient concerns: The patient presented with generalized seizures, short-term memory loss, and a polypoid mass located high in the nasal cavity.

Interventions: He underwent surgical resection of the tumor and postoperative chemoradiotherapy with concurrent intra-arterial cisplatin administration.

Diagnosis: Pathological examination indicated an ONB admixed with craniopharyngioma.

Outcomes: The patient's neurological symptoms gradually diminished after surgery. No evidence of recurrence was observed during a 4-year follow-up.

Lessons: We reported a histologically unusual heterogeneous tumor that comprised ONB and craniopharyngioma. This is the first reported case of PLE with anti-Hu antibodies possibly associated with ONB admixed with craniopharyngioma.

Figure 1

Image of the patient's tumor. (A) A coronal CT image revealed an expansive nasal mass in the patient's left ethmoid sinus that had calcification extending into his maxillary sinus. The cribriform plate, orbit, and nasal septum were not involved. (B) A coronal MRI of the patient's brain and nasal and paranasal cavities showed an enhanced image of the tumor in the left ethmoid sinus. (C) MR angiography of the patient's sinus showing the maxillary artery (arrow) feeding the paranasal cancer (arrowhead).

Figure 2

FLAIR MRI images of the patient's brain before and after treatment. (A) The image shows intense signals in the patient's bilateral medial temporal lobes and his hippocampus (dotted circular line). (B, C) FLAIR MRI images showing that the intensities in the patient's bilateral hippocampal lobes became less detectable after treatment for the ONB (dotted circular line).

Figure 3

Histopathological features of the patient's tumor. (A) In most of the lesion, the neoplastic cells had uniformly small and round nuclei with little cytoplasm, and had dispersed nuclear chromatin that varied between being coarse and fine in structure (hematoxylin–eosin staining, scale bar = 50 μm). (B) Immunostaining for CD56 (scale bar = 50 μm). (C) In the second lesion, nests of tumor cells of various sizes consisting of squamous epithelial cells with intercellular bridges and obvious keratinization are seen (hematoxylin–eosin staining, scale bar = 50 μm). (D) Immunostaining for 34βE12 (scale bar = 50 μm).