Perforating pilomatricoma: transepithelial elimination or not

Pilomatrical Acanthoma: An Extremely Rare Intraepidermal Variant of Pilomatricoma

ABSTRACT

Pilomatrical differentiation can be observed in a variety of benign and malignant tumors, with the most common prototype being pilomatricoma. Pilomatricoma often presents in the deep dermis or subcutis, and the sole involvement of epidermis is extremely rare. In our current case series, specimens from 5 patients were included with an average age of 68 years. All lesions presented as solitary verrucous or keratotic papules on the extremities, with 1 lesion having a prominent horn. All lesions have a variable mixture of basaloid matrical cells and shadow cells, and all lesions express β-catenin (strong nuclear and cytoplasmic), lymphoid enhancer-binding factor 1 within the matrical component, and pleckstrin homology-like domain family A member 1. The histomorphology and immunoprofile of all lesions are of pilomatrical differentiation, confined to the level of the epidermis. Based on these findings and analogous to the terminology used for other benign intraepidermal proliferations (hidroacanthoma simplex and epidermolytic acanthoma), we propose the term "pilomatrical acanthoma" for these rare lesions.

Optimal Timing of Surgical Excision in Pediatric Pilomatricoma: Association between Clinicopathological Features and Cosmetic Outcomes

Background

The treatment of choice for pilomatricomas is surgical excision; however, data for the optimal timing of treatment and cosmetic outcomes are limited.

Objective

This study aimed to investigate the optimal timing of treatment in pilomatricomas by considering clinicopathological findings and cosmetic outcomes.

Methods

Seventy-three pilomatricomas patients aged ≤15 years were retrospectively reviewed. Patients were classified into early excision (disease duration ≤12 months, group A) and delayed excision groups (disease duration >12 months, group B). Tumor characteristics, and histopathological features with evolutionary stages were assessed. Cosmetic outcomes were evaluated by the Modified Vancouver Scar Scale (MVSS), 5-point patient satisfaction score, and complication rates.

Results

Group A showed better cosmetic outcomes than group B in the MVSS (1.53±1.22 vs. 3.68±1.84), 5-point patient satisfaction score (4.08±0.89 vs. 3.18±1.01), and complication rates (11.8% vs. 36.4%), respectively (p<0.05). Secondary anetoderma, tent sign, calcification, and late regressive stage (evolutionary stage IV) were more common in group B, (p<0.05). Moreover, evolutionary stages showed a positive correlation with mean MVSS (r=0.670, p<0.05).

Conclusion

Early excision (disease duration ≤12 months) provides superior cosmetic outcomes compared to delayed procedures. Early recognition, diagnosis, and management for pediatric pilomatricomas is important to improve overall cosmetic outcomes.

Six cases of perforating pilomatricoma: Anetodermic changes with expression of matrix metalloproteinases

Perforating pilomatricoma (PP) is a rare clinical variant of pilomatricoma presenting as a crusted or ulcerated nodule. Previous reports have suggested that the tumor cells perforate the epidermis through a process of transepithelial elimination. Here, we report six cases of PP and examine the mechanism of transepithelial elimination in PP. Histologically, the dermis above or around the tumor nest exhibited edema, dilated vascular spaces, sparse collagen bundles and absence of elastic fibers, suggesting anetodermic changes in all cases. Immunohistochemistry demonstrated many CD68-positive macrophages around the tumor nests. Matrix metallopeptidase (MMP)-9 and MMP-12 were expressed in the inflammatory cells and tumor cells, and were also present in the epidermis and fibroblasts in all cases. We speculate that in PP anetodermic change caused by MMP and elastases including MMP-9 and MMP-12 may precede elimination of the tumor.

A case of perforating dermatofibroma with floret-like giant cells

Dermatofibromas are slow-growing solitary nodules, composed mostly of a dermal proliferation of spindle cells and epithelioid cells. Some dermatofibromas present with multinucleated giant cells, such as Touton, foreign body, and osteoclast-like cells. We report a case of dermatofibroma containing both Touton giant cells and floret-type cells. A 12-year-old boy presented with a 6-mm, firm, nontender, dusky-red to greyish dermal nodule on his left popliteal fossa. As suggested clinically by the central opening, perforation of the epidermis with partial extrusion of the dermal components, including macrophages and vertically oriented collagen bundles, via transepidermal elimination, were detected. In the upper dermis, collagen trapping and mostly epithelioid cells with many giant cells were seen, while the lower part contained mainly spindle cells in a storiform pattern. Multinucleated giant cells scattered in the upper dermis were mainly floret-type multinucleated giant cells with star-shaped cytoplasmic projections, associated with some Touton giant cells. To our knowledge, this is the first report of a perforating dermatofibroma with floret-type multinucleated giant cells.

Perforating pilomatricoma in a 62-year-old female: a rare case report

Pilomatricoma presents as a single, slow-growing, painless, superficial mass arising from the hair matrix cells, over the hair-bearing areas of the body, especially the head and neck. Perforating pilomatricoma is a rare variant of pilomatricoma presenting as crusted or ulcerated nodule. Here, we report a case of 62-year-old female presenting with rapidly growing noduloulcerative lesion on the left cheek, which on histopathology showed perforating pilomatricoma.

Perforating pilomatricoma with anetodermic epidermis in an adolescent with lymphoma

Pilomatricoma is a benign neoplasm originating from primitive cells of the hair matrix. Occasionally the skin overlying pilomatricomas assumes peculiar clinical features, and anetodermic change of the skin overlying pilomatricomas is sometimes seen, but perforation in pilomatricoma is a rare event. We report a case of perforating pilomatricoma with anetoderma in an adolescent with lymphoma.