Pigmented reticular structures in basal cell carcinoma and collision tumours

BACKGROUND

The dermatoscopic diagnosis of basal cell carcinoma (BCC) is based on well-known specific criteria. Despite the fact that a pigment network is considered a negative feature for the diagnosis of BCC, its detection in a BCC context has been reported in 2.8% of cases.

OBJECTIVES

To determine whether pigment networks or network-like structures might represent a pitfall for the correct diagnosis of BCC.

METHODS

Dermatoscopic images of 412 histopathologically proven BCCs were analysed retrospectively.

RESULTS

Pigment network or network-like structures were detected in 14 of 412 (3.4%) BCCs. Nine of 14 BCCs presented a typical pigment network, due to the association of a BCC lesion with a naevus, solar lentigo or actinic keratosis; two BCCs located on the face showed a pseudonetwork, and three of 14 lesions displayed a network-like structure characterized by light-brown irregularly meshed short linear structures, histopathologically related to a hyperpigmentation of the basal layer of the epidermis.

CONCLUSIONS

The presence of a pigment network in the context of a BCC is uncommon, and it usually reflects the association of BCC with a solar lentigo, naevus or a specific location of the lesion on photodamaged skin.

The significance of eccentric and central hyperpigmentation, multifocal hyper/hypopigmentation, and the multicomponent pattern in melanocytic lesions lacking specific dermoscopic features of melanoma

OBJECTIVE

To examine the significance of eccentric hyperpigmentation (EH), central hyperpigmentation (CH), multifocal hyper/hypopigmentation (MH/HP), and the multicomponent pattern (MCP) in melanocytic lesions lacking specific dermoscopic features of melanoma.

DESIGN

A total of 3367 benign and malignant melanocytic lesions (n = 341 melanomas, excluding lentigo maligna and lentigo maligna melanoma) were examined to identify those lesions lacking specific dermoscopic features of melanoma but having any of the global patterns of EH, CH, MH/HP, and MCP.

SETTING

Dermoscopic images were collected from lesions excised or undergoing sequential digital monitoring from the Sydney Melanoma Diagnostic Centre, a tertiary referral institution located in Sydney, Australia.

MAIN OUTCOME MEASURE

The odds ratio (OR) for melanoma of EH, CH, MH/HP, and MCP.

RESULTS

While EH (OR, 3.3; 95% confidence interval [CI], 2.5-4.6) and MCP (OR, 15.4; 95% CI, 11.9-19.9) were significant predictors of melanoma when total melanomas vs nevi were analyzed, there was no significant difference between the frequency of any of the global patterns in melanomas vs benign nevi lacking specific dermoscopic features of melanoma.

CONCLUSION

Based on our study results and previous prevalence data on these global patterns in benign nevi, we do not believe that lesions with EH or MCP require closer observation than other benign nevi lacking specific dermoscopic features of melanoma.

Hypoepiluminescence microscopy of pigmented skin lesions: new approach to improve recognition of dermoscopic structures

BACKGROUND

Hypoepiluminescence microscopy (HELM) is a new dermoscopic approach for analysis of pigmented skin lesions (PSLs) after surgical excision.

OBJECTIVES

The objective was to verify whether this method could provide additional morphologic information for diagnostic or didactic purposes compared to conventional epiluminescence microscopy (ELM).

PATIENTS AND METHODS

Thirty-one PSLs from 30 patients were consecutively evaluated by ELM and, after excision, by HELM. For HELM examination, the lesion was positioned on a glass slide and illuminated from above with a halogen lamp and from underneath with an LED source. All lesions were subsequently examined histopathologically.

RESULTS

In 11 of 31 (35.5%) lesions, a typical pigment network, as assessed by ELM, appeared bidimensional with HELM. In 9 lesions (9/31; 29%) ELM showed a gray-blue area, while HELM allowed us to distinguish 5 lesions (5/9, 55.5%) with gray area predominant showing a lichenoid lymphocytic infiltration and few melanophages from the other 4 lesions (4/9, 44,5%) with heavy dermal accumulation of pigmented melanocytes or melanophages where a blue area was clearly visible at HELM. In 9 other cases (29%), ELM analysis revealed a central homogeneous dark brown/black pigmentation that in 7 cases was seen under HELM examination to consist of globules.

CONCLUSIONS

HELM is particularly useful in evaluating heavily PSLs or structures located in the reticular dermis.

Blue-whitish veil-like structure as the primary dermoscopic feature of combined nevus

The combined nevus is a clinical simulator of melanoma, and clinical examination alone can be inadequate to diagnose this melanocytic pigmented skin lesion. Dermoscopy is a useful tool to differentiate the features related to each type of nevus. We report two cases of combined nevi dermoscopically characterized by a diffuse blue-whitish pigmentation similar to the blue-whitish veil, suggesting the diagnosis of melanoma.

Dermoscopic Patterns of Acral Melanocytic Nevi and Melanomas in a White Population in Central Italy

OBJECTIVE

To investigate the dermoscopic features of acral melanocytic lesions in a white population in central Italy.

DESIGN

Retrospective review.

SETTING

University dermatology department.

PATIENTS

Six hundred fifty-one Italian subjects, ranging in age from 6 months to 78 years.

MAIN OUTCOME MEASURES

We retrospectively investigated all digital dermoscopic images of acral melanocytic lesions included in our database from January 1996 to May 2005.

RESULTS

We retrieved digital images of 723 benign acral melanocytic lesions in 641 patients (235 males and 406 females; mean age, 26.5 years) and of 10 acral melanomas in 10 patients (7 males and 3 females; mean age, 65 years). Individual lesions were located on the soles (n=520), fingers (n=146), and palms (n=67). Among acral nevi, the parallel furrow (42.1%) was the most common pattern, followed by the latticelike (14.9%), nontypical (13.7%), fibrillar (10.8%), homogeneous (9.3%), globular (5.4%), and reticular (2.1%) patterns. The frequency of distribution of the latticelike, nontypical, fibrillar, and homogeneous patterns significantly differed (P<.001, P=.03, P<.001, and P=.03, respectively) between anatomical sites. Also, 13 acral nevi (1.8%), mainly located on the fingers, showed a new combined pattern (transition pattern) consisting of a brownish black network associated with a parallel furrow or latticelike pattern. All 10 acral melanomas showed a multicomponent dermoscopic pattern.

CONCLUSIONS

In our series of acral nevi, we observed 8 dermoscopic patterns, with varying distribution by anatomical site. Identification of a specific pattern is highly suggestive of the benign or the malignant nature of any given acral melanocytic lesion.