Pigmented skin lesions displaying regression features: Dermoscopy and reflectance confocal microscopy criteria for diagnosis.

Melanomas and nevi displaying regression features can be difficult to differentiate. To describe reflectance confocal microscopy features in benign and malignant pigmented skin lesions characterized by regression features in dermoscopy. Observational retrospective study. Inclusion criteria were presence of dermoscopic features of regression; availability of clinical, dermoscopic and RCM imaging; definite histopathologic diagnosis. The study sample comprised 217 lesions; 108 (49.8%) melanomas and 109 were benign lesions, of which 102 (47.0%) nevi and 7 (3.2%) lichen planus-like keratosis (lplk). Patients with melanoma were significantly older than those with benign lesions (61.9 ± 15.4 vs 46.1 ± 14.8; P < 0.001) and a higher proportion of melanomas displayed dermoscopic regression structures in more than 50% of lesion surface (n = 83/108; 76.9%; P < 0.001). On RCM examination, pagetoid cells were significantly more reported in melanoma group, than in benign lesions (86.1% vs 59.6%; P < 0.001) and were more frequently widespread distributed (65.6% vs 20.0%; P < 0.001) and both dendritic and roundish (36.6% vs 15.4%; P < 0.001) in shape. Aspecific architecture at the dermo-epidermal junction (DEJ) was more commonly seen among melanomas than benign lesions (23.1% vs 11.9%; P = 0.002) with higher presence of dendritic and both dendritic and roundish atypical cells at the DEJ (28.7% vs 18.3% and 19.4% vs 3.7%; P < 0.001, respectively). Focal pagetoid infiltration and ringed or clod patterns were more commonly seen in benign lesion. In conclusion, the correct interpretation of regressing lesions remains a challenge, assessing carefully the extent and characteristics of architectural and cytologic atypia on RCM is an additional piece of the complex puzzle of melanoma diagnosis.

Dermoscopic Features of Basal Cell Carcinoma on the Lower Limbs: A Chameleon!

BACKGROUND: Lower limbs represent an uncommon location for basal cell carcinoma (BCC) and only few reports have described dermoscopic features of BCC in this body site. Since BCCs of the lower limbs frequently display nonclassic BCC dermoscopic criteria, they can simulate other benign or malignant lesions. OBJECTIVE: Our aim was to describe the dermoscopic features of BCC located on lower limbs and to define which criteria were more associated with their benign- or malignant-looking appearance. METHODS: We conducted a retrospective study enrolling consecutive patients with histologically confirmed BCCs of the lower limbs. Lesions were classified in 7 categories according to the clinical and dermoscopic global appearance. Clear BCC, squamous cell carcinoma (SCC) or Bowen disease-like, Kaposi disease-like, melanoma-like, and aspecific pattern were considered malignant-looking lesions; however, seborrheic keratosis-like and dermatofibroma-like were considered benign-looking. To define which dermoscopic criteria were independently associated with benign- or malignant-looking appearance, we conducted a multivariate logistic regression analysis. RESULTS: A total of 81 BCCs were enrolled: 18 (22%) were benign-looking lesions (of which 11 were seborrheic keratosis-like and 7 dermatofibroma-like) and 63 (78%) were malignant-looking BCCs (of which 24 were clear-cut BCCs, 23 SCC-like, 2 Kaposi disease-like, 9 melanoma-like, and 5 had aspecific pattern). Multivariate regression analysis showed that erosions/ulceration and vessels were independently associated with malignant-looking appearance. The most represented vessels were glomerular and polymorphic, which are more frequently encountered in SCC, together with ulceration. CONCLUSION: BCC of the lower legs frequently simulates other benign or malignant lesions, with SCC being the main differential diagnosis.

Dermoscopy of Lymphomas and Pseudolymphomas.

Primary cutaneous lymphomas are a heterogeneous group that includes 2 main groups of primary T- and B-cell lymphomas, which can involve the skin with distinct variability in clinical presentation, histopathology, immunophenotypes, molecular signature, and prognosis. The authors describe the most frequent clinical forms of cutaneous lymphomas and their dermoscopic features. Even if the diagnosis of these entities is still based on a cellular level and the literature on dermoscopy in cutaneous lymphomas is limited and, for several entities it is based only on single case reports/case series, we think that know how they appear also in dermoscopy can be useful for helping in the clinical diagnosis.

Pigmented eccrine poroma: dermoscopic and confocal features.

Eccrine poroma is a rare benign adnexal tumor of epithelial cells originating from the terminal ductal portion of the sweat glands that is typically located on palms and soles, although other cutaneous sites can be affected [1]. It is usually nonpigmented even if there is a pigmented variant that corresponds to 17% of cases and it is usually underdiagnosed, since it is mistakenly confused with other pigmented tumors [2,3]. Dermoscopy and reflectance confocal microscopy (RCM) may assist in the correct diagnosis of this tumor. Herein, we report one case of pigmented eccrine poroma (PEP) that simulated clinically a cutaneous melanoma or a basal cell carcinoma. Dermoscopy and RCM excluded the possibilities of those two diagnoses; the overall confocal findings were suggestive for a benign epithelial tumor. Histology was fundamental to diagnose this lesion as a pigmented eccrine poroma. Even if the diagnosis of eccrine poroma remains histopathological still, as in this case report, noninvasive tools such as dermoscopy and RCM examinations can be of help to rule out the diagnosis of melanoma. Larger studies on this rare pigmented variant of eccrine poroma could shed new light on the identification of specific diagnostic dermoscopic and confocal features.

Micronodular basal cell carcinoma: a distinct subtype? Relationship with nodular and infiltrative basal cell carcinomas.

Micronodular basal cell carcinoma (BCC) may be more difficult to eradicate and prone to recurrence than nodular subtype. The aim of the study was to compare anatomical and histological characteristics of the basal cell carcinomas subtypes and the relationship of the micronodular BCC with other subtypes. Primary BCCs (n = 3074) were classified as superficial, nodular, micronodular, morpheic/infiltrative. The location was head/neck, limbs, chest/abdomen, back or genitals. Fifty-one micronodular BCCs were matched randomly with nodular and infiltrative cases, by age, sex, and tumor site. A modified Clark level was used to classify the tumor depth. Micronodular, nodular and infiltrative BCC were prevalently located in the head/neck (P < 0.0001), while superficial in the other regions (P < 0.0001). The Clark level was comparable between micronodular and infiltrative BCC, while nodular BCC showed a more superficial level than micronodular (P < 0.001) and infiltrative (P < 0.001) BCC. No nodular BCC had level IV and only 37.3% level III, while 92% of both micronodular and infiltrative BCC were level III or IV. The percentage of level IV was 11.8% and 25.5% in micronodular and infiltrative BCC, respectively. In the mid-face/periauricular region, 95.5% of micronodular and 100% of infiltrative cases of were level III or IV, compared to 50% of nodular BCC (P < 0.001). The Clark level of nodular subtype was higher for BCC of mid-face/periauricular than other regions (P < 0.05). It can be concluded that micronodular BCC shows intermediate characteristics compared with nodular and infiltrative subtypes but appears to have a specific individuality making it a distinct subtype.

Anatomic location of Basal cell carcinomas may favor certain histologic subtypes.

BACKGROUND: Differences in age, site, and subtype exist in basal cell carcinoma (BCC). OBJECTIVE: To evaluate whether an independent association exists between the anatomic location and the histologic subtype of BCC. MATERIALS AND METHODS: A series of 3,254 BCCs was examined. The location was the head/neck (n  =  1,766), limbs (n  =  362), trunk (n  =  1,113), or genitals (n  =  13). Subtype was classified as superficial, nodular, micronodular, morpheic-infiltrative, or fibroepithelial. RESULTS: Prevalence of BCCs on the head/neck or chest/abdomen increased with age (p < .001). The prevalence of superficial subtype decreased with age (p < .0001), whereas the prevalence on nodular subtype increased (p < .0001). Subtype was associated with location (p < .0001). The prevalence of superficial subtype was lower among BCCs on the head/neck than other locations (24.9% vs 64.4%, OR 0.18, 95% CI 0.16-0.21). The prevalence of nodular or morpheic/infiltrative subtype was higher among BCCs on the head/neck than other locations, that is, 57.1% versus 29.2%, OR 3.23, 95% CI 2.79 to 3.74 (nodular) and 16.1% versus 4.0%, OR 4.56, 95% CI 3.42 to 6.08 (morpheic/infiltrative). CONCLUSION: Anatomic location and subtype of BCC were associated with age, but the anatomic location was the only independent predictor of histologic subtype. Although a bias by referral patterns may not be excluded, the results suggest that the anatomic location may favor the development of particular BCC subtypes.