Nasopharyngeal carcinoma at the Ahmadu Bello University Teaching Hospital, Zaria: A 22-year histopathological review (1992–2013)

Abstract

Background: Nasopharyngeal carcinoma (NPC) is uncommon cancer with unique geographical variations and strong association with Epstein–Barr Virus. The increasing incidence of NPC in Nigeria in recent years has reinforced the need for more studies to be done. This study aims to determine the frequency, age, and sex distribution as well as the histopathological patterns of NPC seen over a period of 22 years, from 1992 to 2013. Materials and Method: It was a retrospective study of all NPCs diagnosed in the Department of Pathology, Ahmadu Bello University Teaching Hospital from January 1st 1992 to December 31st, 2013. The request forms, histopathology reports, slides, and paraffin-embedded tissue blocks of all histologically diagnosed NPCs within the study period were retrieved and examined. The age, sex and site/nature of the biopsy were extracted. Histopathological diagnosis was in accordance to the 2005 World Health Organization classification. Results: NPC showed a frequency of 0.3% (112 cases) with a significant rise in incidence in the last decade. There was a male preponderance with M: F of 3.5:1. The age range was 6–91 years, mode 40 years, mean age 42.4 years, and peak age of incidence 40–49 years (18.8%). Histologically, nonkeratinizing carcinoma (NKC) was the most common (94.6%) followed by keratinizing squamous cell carcinoma (KSCC, 4.5%) and a single case of basaloid squamous cell carcinomas (bscc, 0.9%). Undifferentiated subtypes made up 79.4% of NKC, 12.7% differentiated and 7.9% mixed. In addition, 44.4% were of Regaud type growth pattern, 34.9% Schmincke type, and 20.6% were mixed. The nasopharynx was the most common site of surgical biopsy (57.1%) followed by the nasal cavity (17.9%) and cervical lymph node (11.6%). Conclusions: NPC showed a recent increase in frequency, a male preponderance and a unimodal age pattern that peaked in the 5th decade with an overall mean age of 42.4 years. NKC over KSCC and a solitary case of BSCC was seen. A significant number of biopsies were from sites outside the nasopharynx, suggestive of advanced disease with poor prognosis.