Mediastinal single nodal relapse of a nasal NK/T cell lymphoma

Abstract

A nasal NK/T cell lymphoma is a very aggressive form of lymphoma. Patterns of relapse after treatment have not been systematically evaluated, and mediastinal nodal relapse at a primary site has never been documented. We describe here a 40-year old man who presented with a nasal obstruction caused by a protruding mass that was identified as a nasal NK/T cell lymphoma. The initial work-up, including chest and abdominopelvic computed tomography (CT) and positron emission tomography (PET), showed no regional or distant metastasis. A CT scan performed following three cycles of chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) showed that the mass had nearly disappeared. Radiation therapy undertaken following chemotherapy was given to the primary site. However, PET performed following radiotherapy revealed a single mediastinal lymphadenopathy, with no evidence of residual tumor in the nasal cavity. A biopsy using video-assisted thoracoscopy (VATS) showed the presence of a recurrent NK/T cell lymphoma with an immunophenotype identical to that of the primary nasal lymphoma. An additional three cycles of CHOP chemotherapy were administered, and the patient remains alive, with no evidence of disease 30 months after the initial relapse. These findings indicate that early detection with PET and prompt surgical excision with the use of VATS can lead to successful treatment of a relapsed nasal NK/T cell lymphoma.

Figure 1

Computed tomography of the paranasal sinus showing a soft tissue density mass in the left middle meatus and associated obstructive sinusitis in the left maxillary sinus.

Figure 2

FDG PET of the nasal cavity at the initial diagnosis. There was a focal hypermetabolic lesion in the left nasal cavity at the initial diagnosis.

Figure 3

FDG PET of the mediastium at the initial diagnosis (A) and at relapse (B). (A) There was no abnormal hypermetabolic lesion in the chest and abdomen at the initial diagnosis. (B) There was increased metabolic activity at the mediastinal lymph node of the AP window (maximal SUV=3.6). Diffuse increased uptake was observed in both thyroid glands, indicative of thyroiditis.

Figure 4

Initial biopsy of the nasal mass showing an extranodal NK/T-cell lymphoma (A, B) and biopsy of the mediastinal lymph node showing tumor recurrence (C, D). (A) Viable tumor cells show perivascular distribution in an extensively necrotic background containing an abundance of apoptotic bodies. Note the irregular, hyperchromatic nuclei and variable amount of clear to eosinophilic cytoplasm of the tumor cells (×4000, H and E staining). (B) In situ hybridization for Epstein-Barr virus showing signals in the tumor cell nuclei. (C) A few scattered atypical medium to large lymphocytes were admixed with small, mature, reactive lymphocytes and numerous histiocytes in the paracortex of the effaced node with hyperplastic high endothelial venules (×400, H and E staining). (D) In situ hybridization for Epstein-Barr virus showing positive signals in the tumor cell nuclei. The pathological and immunohistochemical features of the mediastinal lymph node were identical with those of the nasal mass.