Extranodal natural killer/T-cell lymphoma: a diagnostic dilemma.
BACKGROUND
The diagnosis of extranodal natural killer (NK)/T-cell lymphoma (NK/T-cell lymphoma) is often difficult and any delay in its diagnosis leads to a worsened prognosis. We analysed the factors that make the diagnosis of this type of tumour difficult.


RESULTS
We retrospectively reviewed the medical records of 20 patients with NK/T-cell lymphoma treated in our department, and assessed the clinical features and laboratory findings of the cases. Moreover, we classified factors related to delays in diagnosing NK/T cell lymphoma as follows: (1) insufficient specimen size, (2) massive necrosis, (3) large number of inflammatory cells, and (4) poor atypia. We selected cases requiring two or more biopsies for correct diagnosis and checked which factors were the main cause of misdiagnosis.


RESULTS
The average period required for a correct diagnosis was 12.8 months. The most frequent factor leading to diagnostic delay was inflammatory cell infiltration.  Massive necrosis and poor atypia were also important factors in diagnostic delay.


CONCLUSIONS
In cases with necrotic lesions of the nose or pharynx, the possibility of NK/T cell lymphoma should be explored and samples, of as large a size as possible, should be obtained together with EBER-ISH for pathological examination.  Repeat biopsies should also be performed for diagnosis.
Department of Otorhinolaryngology, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
H
H
Yanagi
Y
Y
Nakamura
D
D
Takagi
K
K
Kubota
D000328:Adult; D000368:Aged; D001706:Biopsy; D057210:Delayed Diagnosis; D003937:Diagnosis, Differential; D004724:Endoscopy; D005260:Female; D006801:Humans; D054391:Lymphoma, Extranodal NK-T-Cell / Q000150:complications / Q000175:diagnosis* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010039:Otorhinolaryngologic Neoplasms / Q000150:complications / Q000175:diagnosis* / Q000628:therapy; D011379:Prognosis; D012189:Retrospective Studies