Dermabrasion in Acquired Melanocytic Nevi: A Histopathological and Immunohistochemical Study

A case of subcutaneous metastatic malignant melanoma of the left medial ankle: a case report and review of literature

BACKGROUND

Although rare, melanoma confined to the dermis or subcutaneous tissue without evidence of a primary cutaneous site should provoke consideration of melanoma of unknown primary. This diagnosis carries a favorable prognosis when compared with cutaneous metastatic melanoma. Several hypotheses have been proposed for how melanoma of unknown primary develops, two of which were considered in our patient case: (1) spontaneous regression of the primary tumor following metastasis or (2) the traumatic implantation of ectopic melanocytic cells in other tissues, such as the subcutaneous tissue. Although not a true example of melanoma of unknown primary, our case is still noteworthy as it represents a unique instance of melanoma presenting subcutaneously from trauma to a preexisting epidermal nevus.

CASE PRESENTATION

We present the case of a 66-year-old non-Hispanic Caucasian male who initially sought evaluation for a nontender lump of the left groin. Ultrasound-guided needle biopsy demonstrated stage III malignant melanoma. Upon further history taking, it was discovered that he had a nevus of the left medial ankle that was subjected to traumatic removal. He later developed a subcutaneous nodule at the same site. Positron emission tomography scan results supported the histopathologic findings which demonstrated invasive melanoma centered in the subcutaneous tissue without an epidermal component. Following left inguinal lymph node dissection, the patient received adjuvant immunotherapy and radiation to the left inguinal area. At 6 months following completion of therapy, metastases were identified in the lungs, vertebra, ribs, and liver. The patient is currently receiving immunotherapy with ipilimumab-nivolumab.

CONCLUSION

As our patient did not have a readily apparent primary epidermal melanoma site at presentation, consideration was given as to whether this case may represent a melanoma of unknown primary, as originally defined by Das Gupta. This case does not meet the proposed criteria, however, as the patient reported a preexisting nevus in the area that was subjected to traumatic removal. Instead, we postulate that this trauma allowed for implantation of melanocytes into the subcutaneous tissue that later resulted in a malignant melanoma.

Myocutaneous sliding flap for reconstruction of divided eyelid nevus

OBJECTIVE

To evaluate the myocutaneous sliding flap for restructuring the eyelid of divided nevus, thus optimizing the aesthetic outcome.

DESIGN

A retrospective clinical study.

PARTICIPANTS

Clinical data from patients with a small or medium-sized divided nevus of the eyelids between January 2015 and December 2018 in the Shanghai Ninth People's Hospital were reviewed.

METHODS

The safety and efficacy of a surgical approach using a myocutaneous sliding flap were evaluated based on postoperative features and complications.

RESULTS

This study included 53 patients with an average age was 21.6 years (range, 2-68 years). The lesions involved the inner canthus in 5 patients (9.43%) and the lateral canthus in 14 patients (26.42%). Three (5.66%) patients had undergone primary surgery elsewhere. Overall, the eyelid margins were in good shape postoperatively at an average follow-up of 22.7 months, and there were no obvious eyelid deformities, lagophthalmos, or other unacceptable complications postoperatively. The nevi were benign intradermal (60.38%), junctional (16.98%), and compound types (22.64%) without malignant transformation, as confirmed by pathologic examination. No malignant transformation was observed until the end of the follow-up period.

CONCLUSION

A myocutaneous sliding flap can provide an appropriately size pedicle graft and achieve satisfactory cosmetic results for divided eyelid nevus.

Dermoscopic Aspects of Traumatized Nevi After Dermabrasion

BACKGROUND

Melanocytic nevi submitted to trauma can undergo clinical, dermoscopic, and even histological changes, making it difficult to differentiate them from a melanoma.

OBJECTIVE

The aim of this study is to evaluate the dermoscopic changes of traumatized nevi after dermabrasion.

METHODS

Dermoscopic images of acquired melanocytic nevi were compared before and 4 weeks after half of their area had undergone dermabrasion.

RESULTS

The sample consisted of 50 lesions from 15 patients. The homogeneous pattern was the most frequent, followed by the reticular, cobblestone, and globular patterns. After dermabrasion, nearly half of the lesions (46%) became dermatoscopically asymmetric. Among all lesions, structureless areas, dotted vessels and erythema were the most frequent new dermoscopic structures.

CONCLUSION

Trauma after dermabrasion may induce significant dermoscopic changes in melanocytic nevi. Although the global pattern did not change, most of the lesions became asymmetric, with the appearance or fading of dermoscopic structures and colors. A history of recent trauma should be investigated when evaluating pigmented lesions.

On the development of neurocutaneous units--implications for the histogenesis of congenital, acquired, and dysplastic nevi

This study of spontaneous abortions and fetal deaths in utero used immunostains to evaluate the structure of developing cutaneous nerves. Melan-A immunostains were also used to screen 25 cases of grossly normal fetal skin for occult fetal nevi. Discrete portions of epidermis were generally supplied by branches emanating from regularly spaced deep cutaneous nerves, producing a wedge shape, interpreted as neurocutaneous units (NCU). Deeper nerves embraced broader portions of epidermis. Some nerves ran parallel to epidermis, especially near the superficial vascular plexus at the junction of superficial and deep dermis. Nerve sheath stem cells in each NCU may supply the melanocytes needed by the corresponding portion of epidermis. Transformed nerve sheath stem cells may lead to formation of occult prenatal nevi, whose histology and histogenesis may best be understood in terms of NCUs. In particular, the size and shape of a nevus may be largely determined by its NCU of origin. Six fetal nevi were detected, and 3 occult lumbosacral Mongolian spots; all in deep dermis, no later than the middle of the second trimester, mainly with a pattern of singly dispersed deep dermal melanocytes. These findings suggest that congenital (prenatal) nevi begin as intradermal nevi. In addition to explaining congenital nevi, these findings have implications for the histogenesis of acquired (postnatal) nevi and dysplastic nevi.