Two of ocular oncology’s leaders, Drs. Carol Shields and Jerry Shields, analyzed 5,000 cases of conjunctival tumors seen during their 40 years of practice to provide comparative analysis of the 3 most common malignancies and their benign/premalignant counterparts.
In general, lesions with larger median basal diameters and presence of feeder and/or intrinsic vessels were found to be malignant, though the paper provides greater detail for each comparison. Recognizing early factors associated with malignancy will help guide optimal management of a conjunctival tumor.
Out of 5002 cases, 52% were benign, 18% premalignant, and 30% were malignant. Statistical analysis showed significant differences in the clinical features of malignant tumors compared to the benign/premalignant counterparts that they arise from and/or resemble.
Comparing primary acquired melanosis (PAM) and melanoma, melanoma is more prevalent in older, male, white patients (P<0.001 for all). Melanoma is more likely to be located in the fornix or tarsus, have greater median basal diameter and thickness, higher presence of intralesional cysts, feeder vessels, intrinsic vessels and hemorrhage (P£0.018 for all).
The factors conveying the greatest risk for melanoma compared with PAM were greater than 1 mm thickness ([RR=] 2.8), lack of pigmentation (2.4), presence of feeder (2.3) and intrinsic (2.2) vessels, cysts (2.1), hemorrhage (1.8), older age (1.7), and tarsal location (1.6). The authors put these risks into clinical context by calculating that a patient >60 years of age presenting with a melanocytic lesion >1mm with feeder and intrinsic vessels is 24 times more likely to have melanoma than PAM.
Comparing conjunctival intraepithelial neoplasia (CIN) and squamous cell carcinoma (SCC), the latter displayed significantly greater diffuse involvement, location >1 mm from the limbus, brown pigmentation, median basal diameter, thickness, and amount of intrinsic vessels. Presence of pigmentation and diffuse configuration were associated with 1.6-fold greater risk for SCC vs CIN.
For benign reactive lymphoid hyperplasia (BRLH) compared with lymphoma, lymphoma occurred in patients of significantly older median age, the lesions showed larger median basal diameter, were less typical in the nasal region, and were more often in the fornix location (P<0.0001 for all). The greatest RR for lymphoma (vs BRLH) included older age (2.6); location superior (1.4), inferior (1.4), both nasal and temporal (1.7), and diffuse (1.6) (compared with nasal location); and large basal diameter (1.4).
Some limitations of this study include the enrollment of patients evaluated at a tertiary ocular oncology center, which likely over-represents serious malignancies and under-represents less serious conditions. This factor, combined with the predominantly white patient database, could account for the few cases of racial melanosis and many cases of suspicious melanocytic lesions – known to be over 2 times more prevalent in whites compared to blacks.
Nevertheless, this paper represents the first statistical analysis on the differences between 3 important malignancies and their malignant/pre-malignant counterparts. Recognizing features associated with malignancy is essential for making clinical and surgical decisions when a patient presents with a conjunctival tumor.