Accuracy of clinical diagnosis of skin lesions.
BACKGROUND
Skin cancer is an increasing problem in fair-skinned populations worldwide. It is important that doctors are able to diagnose skin lesions accurately.


OBJECTIVE
To compare the clinical with the histological diagnosis of excised skin lesions from a set of epidemiological data. We analysed diagnostic accuracy stratified by histological subtype and body site and examined the histological nature of misclassified diagnosis.


METHODS
All excised and histologically confirmed skin cancers in Townsville/Thuringowa, Australia from December 1996 to October 1999 were recorded. Positive predictive values (PPVs) and sensitivities were calculated for the clinical diagnoses and stratified by histological subtype and body site.


RESULTS
Skin excisions in 8694 patients were examined. PPVs for the clinical diagnoses were: basal cell carcinoma (BCC) 72.7%; squamous cell carcinoma (SCC) 49.4%; cutaneous melanoma (CM) 33.3%. Sensitivities for the clinical diagnosis were: BCC 63.9%; SCC 41.1%; CM 33.8%. For BCC, PPVs and sensitivities were higher for the trunk, the shoulders and the face and lower for the extremities. The reverse pattern was seen for SCCs.


CONCLUSIONS
Diagnostic accuracy was highest for BCC, the most prevalent lesion. Most excisions were correctly diagnosed or resulted in the removal of malignant lesions. With nonmelanocytic lesions, doctors tended to misclassify benign lesions as malignant, but were less likely to do the reverse. Although a small number of clinically diagnosed common naevi subsequently proved to be melanoma (6.3%), a higher proportion of all melanomas had been classified as common naevi (20.9%). Accuracy of diagnosis was dependent on body site.
Heal
C F
CF
Skin Cancer Research Group within the North Queensland Centre for Cancer Research, School of Medicine and School of Public Health, Tropical Medicine and Rehabilitation Sciences, James Cook University, Townsville, Qld, Australia. clare.heal@jcu.edu.au
Raasch
B A
BA
Buettner
P G
PG
Weedon
D
D
D000328:Adult; D000368:Aged; D001315:Australia; D002280:Basal Cell Carcinoma / Q000175:diagnosis / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000473:pathology; D002983:Clinical Competence; D003880:Dermatology; D005188:False Negative Reactions; D005189:False Positive Reactions; D005194:Family Practice; D005260:Female; D006801:Humans; D008297:Male; D008545:Melanoma / Q000175:diagnosis / Q000473:pathology; D008875:Middle Aged; D009506:Nevus / Q000175:diagnosis / Q000473:pathology; D009508:Nevus, Pigmented / Q000175:diagnosis / Q000473:pathology; D010338:Pathology, Clinical / Q000592:standards*; D011237:Predictive Value of Tests; D012871:Skin Diseases / Q000175:diagnosis* / Q000473:pathology; D012878:Skin Neoplasms / Q000175:diagnosis / Q000473:pathology