Acquired perforating collagenosis (APC) is a rare dermatological condition characterized by the spontaneous eruption of skin-colored or erythematous papules or nodules that eventually ulcerate and exude collagenous material. The exact etiology of APC remains unclear, although various triggers, including infections, medications, autoimmune diseases, and trauma, have been implicated.

This case report presents a 63-year-old female with a history of diabetes who developed erythematous papules and plaques topped with thick, yellowish, hyperkeratotic, adherent crusts on the upper back following an insect bite. Histopathological examination confirmed the diagnosis of APC, characterized by a cup-shaped invagination in the epidermis containing degenerated collagen bundles and basophilic material. Masson-trichrome staining showed transepidermal elimination of the collagen fibers. Patient was initially prescribed tretinoin 0.1% cream to be applied 2x a day. However, patient was not able to apply prescribed medications. Interestingly, without any specific treatment, the patient’s symptoms gradually improved over 3 months and eventually resolved completely.

This case report highlights the spontaneous resolution of APC in a patient following an insect bite. While most cases of APC require medical intervention, this case demonstrates the potential for spontaneous healing in certain individuals. Further research is needed to understand the factors that influence the course of APC and to identify potential predictors of spontaneous resolution.

Human ; Female ; Middle Aged: 45-64 Yrs Old ; Collagen ; Insect Bites ; Insect Bites And Stings

Multiple Familial Trichoepithelioma (MFT) is a subtype of trichoepithelioma that begins during childhood as asymptomatic skin colored nodules predominantly on the central area of the face. It is a rare benign tumor of follicular differentiation associated with syndromic disorders and with mutations on the following genes: PTCH, 9p21 and CYLD. Overlap features between trichoepitheliomas and basal cell carcinomas may be present clinically and histopathologically. Hence, the importance of clinicopathologic differentiation between both as treatment options and prognosis varies.

We have a 52 year old male who presented with multiple asymptomatic, coalescent, flesh colored papules and nodules on the face and on the bilateral ears that started during childhood with gradual progression in size. Dermoscopy revealed thin arborizing vessels, milia-like cysts on a whitish background. History of similar lesions are noted among eight of his family members. Skin biopsies were taken on two nodules which showed tumor islands of basaloid cells with peripheral palisading, surrounded by fibrous stroma, characteristic papillary mesenchymal bodies and presence of keratin filled cysts. Genetic testing was advised and the planned course of action for the patient is to undergo ablative carbon dioxide laser combined with topical imiquimod cream to minimize recurrence.

This case highlights the relevance of multiple biopsy sites to rule out other differential diagnoses presenting with leonine facies and syndromic disorders associated with multiple familial trichoepitheliomas. Genetic testing is recommended but presumptive diagnosis may be made through positive family history, clinical and histopathologic features.

Human ; Male ; Middle Aged: 45-64 Yrs Old ; Multiple Familial Trichoepithelioma ; Familial Cylindromatosis