Fever of unknown origin and pharyngitis as harbingers of natural killer/T-cell lymphoma: A case report highlighting diagnostic challenges

Abstract

Fever of unknown origin is one of the most challenging clinical symptoms, with complex etiologies including infections, malignancies, and rheumatic immune diseases. Lymphoma is a common malignant tumor associated with fever of unknown origin, and its early diagnosis is often difficult because routine laboratory tests and imaging manifestations may fail to provide a definitive diagnosis. Here, we report the case of a patient with natural killer/T-cell lymphoma who primarily presented with long-term fever and pharyngodynia. The patient sought medical care at several hospitals and underwent multiple laryngoscopies and a biopsy of the tongue base. After >3 months from the time of initial presentation, the diagnosis was ultimately confirmed through the second biopsy of the tongue base. The case highlights the diagnostic challenges of lymphoma with atypical symptoms in the context of fever of unknown origin and underscores the role of infectious disease physicians in diagnosing noninfectious diseases related to fever of unknown origin.

Keywords: Fever of unknown origin; infectious disease physician; lymphoma; natural killer/T-cell lymphoma; noninfectious diseases.

Figure 1.

Laryngoscopy results before admission: multiple ulcers were observed on the tongue base and pharynx, with an ulcer-like neoplasm visible on the tongue base, and the epiglottis was absent (the neoplasm is indicated by the red circle).

Figure 2.

Physical examination on Day 0: A white coating was visible on the tongue, with multiple ulcers in the pharynx. An ulcer-like neoplasm was observed at the base of the right side of the tongue (indicated by the red circle).

Figure 3.

The PET–CT image on Day 4 showing localized thickening of the mucosa and increased glycol metabolism in the soft palate, left lateral wall of the oropharynx, base of the tongue, and left anterior wall of the hypopharynx. PET–CT: positron emission tomography–computed tomography.

Figure 4.

Pathology of tongue base biopsy on Day 6. (a) Right tongue base mass: sheets of convoluted cells with prominent nucleoli and visible mitotic figures were observed in the dermis and intermuscular tissue; (b) IHC image (EBER-ISH, 4.00×); (c) IHC image (EBER-ISH, 20.00×); (d) IHC image (CD2, 20.00×); (e) IHC image (CD30, 20.00×) and (f) IHC image (vimentin, 20.00×). IHC: immunohistochemistry.

Figure 5.

Timeline of investigations and interventions.