Abstract Eruptive disseminated Spitz nevi is a rare clinical presentation that features an abrupt widespread eruption of Spitz nevi. Spontaneous regression of these nevi has been rarely reported in previous literature. The authors of the present study report the case of a 30-year-old man who presented eruptive disseminated Spitz nevi that appeared within a week and started regression in the following years.

Abstract Spitz nevus is a benign melanocytic lesion, which presents in several ways: solitary, agminated, or disseminated. The disseminated variant is uncommon; it may have a rapid evolution (the eruptive form) and be difficult to manage. This report presents the case of a 24-year-old patient with multiple papules on his limbs, which had appeared four years previously. On physical examination, 120 pink and skin-colored papules were seen, which under dermoscopy were observed to be homogeneous, pink vascular lesions. Histopathologic study revealed epithelioid cells arranged in groups or singly in the dermis and dermo-epidermal junction. They were HMB-45 positive in the superficial dermis, and Ki-67 < 1%. Given these findings, a diagnosis of eruptive disseminated Spitz nevi was made.

Abstract: Background: Pigmented lesions on acral sites are common; clinical differentiation of nevi and early melanoma can be challenging. In these cases, dermoscopy can provide a more accurate diagnosis. Most dermoscopic patterns on acral skin have been described in Asian and European populations, while there are few studies in Latin American populations. Objectives: To determine the frequency of pigmented lesions in volar skin and their dermoscopic patterns in a Mexican population. Methods: An observational, descriptive, cross-sectional study was performed in Hispanic patients with the presence of at least one pigmented lesion on acral skin. Clinical and dermoscopic images were obtained. These were subsequently evaluated independently by two dermatologists trained and experienced in dermoscopy. Results: A total of 582 pigmented lesions on volar skin were diagnosed in 321 patients. Overall, prevalence of acral pigmented lesions on volar skin was 6.8%. For both observers, parallel furrows were the most frequent pattern described, but for observer 2, a lattice-like pattern was prevalent on the toes and a homogeneous pattern on the sides of the feet. There was lower inter-observer agreement, with a kappa index of 0.144. Study limitations: The lesions were not biopsied, so clinical-histological correlation could not be performed. The study did not correlate dermoscopic patterns with age. Conclusions. As previously reported by other authors, parallel furrows were the most frequently found dermoscopic pattern on palmoplantar skin.

Abstract: We report a case of a 76-year-old patient with a history of recent weight loss and ulcerated umbilical nodular lesion. Initially, we considered the diagnostic hypothesis of Sister Mary Joseph's nodule. However, histopathological evaluation revealed that it was an ulcerated intradermal nevus. We perform a brief review of umbilical nodules.

Abstract Onychocytic matricoma is a newly described tumor of the nail matrix. Clinically, it presents with localized thickening of the nail plate and melanonychia. Histologically, it represents a benign acanthoma of onychocytes. There are 8 cases reported in the literature. A 12-year-old girl presented with localized melanonychia and concurrent thickening of the nail plate restricted to the area of pigmentation affecting the right thumb, with no history of trauma or pain. We report a case of this rare tumor occurring in late childhood and provide a comprehensive review of its clinical presentation and differential diagnosis. Both clinicians and dermatopathologists should be aware of the presentation of onychocytic matricoma and include it in their scope of diagnosis of longitudinal nail bands.

AbstractBACKGROUND:Hair follicle nevus is a rare, congenital hamartoma with follicular differentiation characterized histologically by numerous, tiny, mature hair follicles. Trichofolliculoma, the histopathological features of which are quite similar to those of hair follicle nevus, is also a hamartoma that differs from hair follicle. Accessory tragus is a relatively common, benign congenital abnormality of the external ear with an incidence rate of 1 to 10 per 1,000 live births.OBJECTIVE:This study seeks to assess the discriminatory value of currently available, histological criteria in the differential diagnosis of hair follicle nevus, accessory tragi and trichofolliculoma.METHODS:Twenty-one patients comprising 9 cases of hair follicle nevus, 8 accessory tragi patients and 4 trichofolliculoma cases, were recruited to perform the study.RESULTS:There were 10 males and 11 females in the study group. No significant difference was observed between the three study groups in terms of age, gender or histopathological parameters such as density of hair follicles, subcutaneous fat score and presence of connective tissue framework. Cartilaginous component was seen in 8 cases that were diagnosed as accessory tragi, while central cyst and radiating hair follicles were seen in 4 cases which were diagnosed as trichofolliculoma.CONCLUSION:The results of our study showed that diagnostic discrimination of these diseases could be made only with the clinicopathologic correlation because of their clinical and histopathological similarities.

Abstract A 13-year-old boy presented congenital, raised, yellowish colored plaques with fibroelastic consistency, which were velvety in appearance, alopecic, with clearly defined limits and sulci or well-marked meandering invaginations, a cerebriform appearance on the upper part of the right ear, accompanied by alopecia in the temporomandibular region-parietal. The lesion was asymptomatic. Histopathologic examination revealed acanthosis, hyperkeratosis, papillomatosis and follicular plugging in the epidermis. The upper dermis showed underdeveloped hair follicles with sebaceous glands, consistent with sebaceous nevus. There were no skeletal, cardiological, ophthalmological or neuropsychomotor changes; nor were there any records of relevant pathologies in the family history. The patient complained of his appearance, experiencing aesthetic and social issues. Following a diagnosis of cerebriform nevus sebaceous, complete excision was performed with excellent aesthetic results.

Abstract Atypical and unusual locations of psoriasis are very frequent. However, localized linear psoriasis is rare, with few cases described in the literature. It is characterized by a linear distribution of psoriasis lesions along Blaschko lines. We report the case of a three years old child, who presented unilateral erythematous scaly plaques arranged along Blaschko lines in the left hemithorax, with no associated symptoms and no lesions in other parts of the body. The differentiation of linear psoriasis from other linear dermatoses is not easy. The combination of a thorough history, a careful examination of the skin and histopathology are essential to ensure the correct diagnosis and appropriate treatment.

Abstract Elastoma is a connective tissue nevus characterized by changes in elastic fibers. It can be congenital or acquired, and is usually diagnosed before puberty. Associated with osteopoikilosis, it is known as Buschke-Ollendorff syndrome. Histopathology with specific staining for elastic fibers is critical for a diagnostic conclusion. This report describes the case of a 7-year-old male patient with lesions diagnosed as elastoma, with absence of bone changes in the radiological imaging. This study aims to report the clinical presentation and histological examination of such unusual disease.