Skin tumors at the Lagos University Teaching Hospital, Nigeria.

INTRODUCTION: Skin tumours can be malignant or benign. Skin cancer is the most common malignancy among Caucasians and noted to be rare in Africans and negroid skin. In view of the rarity of skin cancers in Africans, there is delayed diagnosis; and consequent advanced presentation and poor prognosis. OBJECTIVE: This is to document the frequency of skin tumours (benign and malignant) from a 7-year review (January 2001 to December 2007) of histology reports of all skin samples seen at the pathology department of the Lagos University Teaching Hospital. METHODS AND MATERIALS: Reports of all skin samples seen at the pathology department between January 2001 and December 2008 were reviewed. The frequencies of various skin tumours (both benign and malignant) were determined and the result displayed using frequency tables. RESULTS: Skin tumours represented 19.8% of all reports made on skin during the study period. One hundred and twenty one (68.7%) were benign tumours while 55 (31.2%) were malignant tumours. There is a female preponderance for both malignant and benign tumours. The male to female ratio was 1:1.28 for benign tumours and 1:1.39 for malignant tumors. Squamous cell carcinoma (SCC) was the commonest malignant tumor, followed by malignant melanoma, Kaposi's sarcoma and dermatofibrosarcoma protuberans. Cutaneous papilloma was the commonest benign tumour. CONCLUSION: A wide range of skin tumours, benign and malignant were documented; hence there is need for more vigilance in order to diagnose them early.

KRAS and BRAF mutations in Nigerian colorectal cancers.

PURPOSE: Activation of the KRAS oncogene is implicated in colorectal carcinogenesis and mutations have been reported in 30-50% of cases. BRAF mutation, though less common, is also reported and importantly associated with shorter progression-free interval. This study aims to determine the KRAS and BRAF mutation statuses of Nigerian colorectal cancers (CRC). METHODS: Mutation analysis was carried out on archival paraffin-embedded blocks of CRC tissues. KRAS codons 12, 13 and 61 and BRAF V600E were assessed by pyrosequencing after DNA extraction from 200 cases at the Leeds Institute of Molecular Medicine, St. James's University Hospital, UK. Mutation rates and the spectra were determined. RESULTS: Pyrosequencing was successful in 112 of 200 cases. KRAS mutation in codons 12 and 13 was demonstrated in 23 of 112 cases (21%); none in codon 61. BRAF mutation in codon 600 was demonstrated in 4.5%. CONCLUSION: This study shows that 21% of Nigerian CRC patients carry a KRAS mutation; half the rate in Caucasians; and that BRAF mutation also occurs in Nigerian CRC cancers.

Primary bone tumours in a tertiary hospital in Nigeria: 25 year review.

BACKGROUND: Primary bone tumors remain a daunting challenge to orthopaedic surgeons. The challenge is heightened in developing countries due to limited diagnostic and therapeutic facilities and ignorance. The published literature on the subject is sparse in our environment. OBJECTIVE: To describe the pattern of primary bone tumors seen in a tertiary hospital in Nigeria. METHODS: This is a retrospective review of all the histologically confirmed primary bone tumours seen at Lagos University Teaching Hospital (LUTH) over a 25 year period. RESULTS: A total of 242 patients (aged 7.5 to 62 years) with a mean of 25.3 years were studied. One hundred and forty four patients (59.5%) were males and 98 (40.5%) were females. The peak age incidence was in the age group 11-20 years. One hundred and thirty (53.7%) of the tumors were benign. Among these Osteochondroma was the commonest accounting for 36 cases (27.7%) followed by Osteoclastoma, 28 cases (21.5%). Osteosarcoma accounted for 66 cases (58.9%) of all primary malignant tumours in the study. CONCLUSION: This study showed that primary bone tumours were mainly benign, occurred predominantly in the second decade of life with a male preponderance. Osteochondroma and Osteosarcoma were the most common benign and primary malignant bone tumours respectively.

Nucleolar organizer regions in jaw tumours of cartilaginous origin.

Nucleolar organizer regions [NORs] are loops of DNA that transcribe to ribosomal RNA. They can be visualized as intranuclear black dots by histochemical staining with a colloid silver solution. Silver-stained nucleolar proteins [AgNORs] were counted in cases comprising of primary chondrosarcomas of three histologic grades, in chondromyxoid fibroma and in controls comprising of normal bone and cartilage tissues of the jaw bones. The AgNOR counts increased step-wisely from normal bone tissue [1.11 0.4], chondromyxoid fibroma [2.66 0.78], grade I chondrosarcoma [3.94 0.34], grade II chondrosarcoma [4.32 0.52], and grade III chondrosarcoma [5.54 0.44]. There was a statistically significant difference in the mean AgNOR counts between grade 1 and grade III chondrosarcoma [p < 0.05]. The mean AgNOR counts for benign cartilaginous [chondromyxoid fibroma] tumour was significantly lower than the mean, AgNOR count for malignant cartilaginous tumours [chondrosarcomas] [p < 0.05]. The results in the present study indicate that silver colloid staining is a useful technique for evaluating the proliferative activity of chondrosarcoma and benign cartilaginous tumour such as chondromyxoid fibroma.

Evaluation of nucleolar organizer regions in tumours of the jaw bones.

Nucleolar organizer regions [NORS] are loops of DNA that transcribe to ribosomal RNA. They can be visualized as intranuclear black dots by histochemical staining with a colloid silver solution. Silver stained nucleolar proteins (AgNORs) were counted in a variety of jaw bone tumours. In osteosarcomas, the number of AgNORs was also quantified before and after chemotherapy. Malignant bone tumour cells possessed more than five small AgNORs (5.54 +/- 0.44). Nuclei of benign jaw bone tumour cells had less than three (2. 97 +/-0.61). A significant difference in the number of AgNORs between osteosarcoma before chemotherapy (5.76 +/- 0.50) and after chemotherapy (3.89 +/- 1.65) was observed. (P < 0.05). The number ofAgNORs in recurrent osteosarcoma, recurrent ameloblastic carcinoma and recurrent chondrosarcoma was much higher than in their respective primary lesion but without statistical significant difference. The results of the present study indicate that the AGNOR count might help in determining malignancy, evaluating the effect of chemotherapy, and deciding the prognosis.