The Evaluation of the Malignant Characteristics of Conjunctival Lesions Based on the Dermatoscopic Algorithm

Abstract

Background/Aim: This study analysed the prevalence of the characteristics evaluated in dermatoscopy for melanocytic infiltrations of the conjunctiva with various degrees of malignancy. Patients and Methods: A total of 160 conjunctival pigmented lesions were studied. Each lesion was scored using dermatoscopic patterns and the characteristics of malignancy described by Kittler. Also, the Authors' own clues were added to the evaluation. Results: In melanomas, the following characteristics were identified: asymmetry of the pattern and colour, larger average number of colours, the presence of grey colour, structureless area, polymorphic vessels and feeder vessels. A pattern of black dots and a black colour was typical of malignant lesions and pre-cancerous (premalignant) lesions -primary acquired melanosis (PAM) with atypia. Cysts were observed only in the group of naevi. Conclusion: The patterns evaluated with dermatoscopy are present in pigmented lesions of the conjunctiva. There are, however, some characteristics which allow differentiation between melanoma and pigmented naevus and melanosis and also between PAM.There are several lesions that arise from the melanocytes of the conjunctiva. The most common are naevi, primary acquired melanosis (PAM) and malignant melanoma (MM). The predominant conjunctival pigmented tumour is naevus (1, 2). Naevus accounts for 28% of all conjunctival tumours and 52% of melanocytic lesions (3). It is a benign lesion, with a less than 1% (3, 4) tendency to malignant transformation. It is usually a unilateral, slightly elevated, variably pigmented lesion, with clear cysts, and feeder vessels, and is predominantly located in the bulbar conjunctiva (3). All naevi require serial observation using photographic documentation. Any changes in size, shape or colour are suspicious of malignant transformation and should be treated like melanoma. Some patients demand excision for cosmetic reasons (4, 5).PAM accounts for 11% of all conjunctival tumours and 21% of conjunctival pigmented lesions (2, 6, 7). It can be divided into melanosis with atypia and without atypia, depending on the nuclear features and growth pattern of melanocytes in the histopathological examination. The presence of atypia is associated with a very high risk (13-50%) of malignant transformation, while absence of atypia carries no risk for melanoma development (4-6). PAM with atypia is considered to be a form of melanoma in situ, similar to lentigo maligna of the skin (6, 8). PAM occurs as a flat, unilateral, brown, patchy or diffuse lesion usually in middleaged Caucasian individuals (9). It is thought that it is impossible to distinguish clinically PAM without atypia from PAM with atypia (4). PAM must be differentiated from racial melanosis, which is usually bilateral and symmetrical (6). The procedure proposed by Shields and co-workers in patients with PAM involves observation or surgical treatment in combination with cryotherapy and/or topical chemotherapy depending on the size of the lesion. In cases of very large tumours, ...

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Dermoscopy of melanoma according to different body sites: Head and neck, trunk, limbs, nail, mucosal and acral

“…Conjunctival melanomas are mainly characterized by a dark brown pigmentation [73][74][75] organized in irregularly distributed dark brown and black dots that can be confluent in a structureless pattern. 74 Grey colour is also observed in more than half of the cases.…”

Diagnostic Algorithm for Conjunctival Melanocytic Lesions

“…Each conjunctival lesion, which was qualified for excision, was re-assessed by 3 independent ophthalmologists, specialising in ocular oncology, according to the previously described (19) protocol of ophthalmological examination developed for the purposes of this work. The tumours were described on the basis of eye biomicroscopy, without preliminary diagnosis.…”

“…It was then verified whether there was any evidence of malignancy (clues of malignancy) in the melanocyte lesion as described by Kittler, such as a grey structureless area, an eccentric structureless zone (any colour except the conjunctiva), polymorphous vessels, and segmental pseudopods (20). Also, the characteristics added in our study were described, comprising cysts, peripheral feeder vessels, and black dots on the entire surface of the lesion (not only located peripherally) (19).…”

“…The objective of our paper was to generate a diagnostic algorithm, which would differentiate between melanomas and other melanocytic conjunctival infiltrations. This would be mainly based on the criteria applied in dermatoscopy, but also taking into consideration the characteristics that are only typical of conjunctival lesions (19,20).…”