Atlas of Dermatopathology
Histological features of reactive perforating collage-nosis (RPC) vary according to stage of disease. The pathological manifestations of lesions that did not form an umbilical fossa in the early stages, degenerate collagen fibers accumulate in dermal papillae and epidermal hyperplasia may be seen. The upper epidermis is atrophied, and a thin layer of keratinized material is visible in the center. Typical acanthosis is visible on both sides of the lesion. In the late stage, epidermis cup-shaped depression can be seen in the epidermis, and it filled with columnar overlying keratin plug that consists of parakeratotic debris, denatured collagen fibers and inflammatory cells.1 The epidermis below is obviously thin. It is locally visible that degenerative collagen fibers pass through the epidermi vertically. The epidermis on both sides of the cup-shaped structure show acanthosis and hyperkeratosis, and infiltration of lymphoid cells is observed in the superficial dermis and around the blood vessels (Fig. 1). Blue-stained collagen fibers are visible in the superficial dermis and epidermis in Masson staining.
RPC is a rare disorder in which abnormal collagen fibers extrude through the epidermis.2 It can be divided into inherited RPC and acquired RPC. The former is more rare, mainly seen in children. The latter is mainly seen in adults and often combined with systemic diseases, such as diabetes, chronic renal failure, particularly in patients undergoing dialysis.
The pathogenesis of RPC is not yet clear, it has a certain genetic predisposition and can be family-aggregated. Previous studies have demonstrated that immunoreactivities of transforming growth factor-β3, matrix metalloproteinase (MMP)-1 and tissue inhibitor of metalloproteinase-1 were significantly increased in the lesions of acquired RPC.3
The disease occurs in the exposed area, usually in the limbs and back, as well as in the face and neck. The clinical manifestations are hard skin colored papules, and often at sites of superficial trauma, mosquito bites, hemorrhoids and after scratching.4 The center has umbilical fossa depressions, which are filled with keratinized substances. The crusts are not easy to remove, and scars and hypopigmentation can be left behind (Fig. 2). Skin lesions can resolve spon-taneously after 6 - 8 weeks, but are prone to recur. Itching symptoms are common, Köbner phenomenon is positive in some patients.5 Some autoimmune diseases are thought to be associated with this disease, such as systemic lupus erythematosus,6 vasculitis, dermatomyositis and Mikulicz disease. In addition, some malignant tumors, including lymphoma, thyroid cancer7 and breast cancer,8 have also been reported as coexisting diseases.
The disease needs to be differentiated from amyloidosis, vasculitis and pruritus in the early stage. Late lesion needs to be distinguished from elastosis perforans sepiginosa, penetrating folliculitis, Kyrle disease, itching nodules, penetrating granuloma annulare and perforating psedoxanthoma elasticum. Histopathological examination can be identified.
There is no specific treatment for this disease. Ultra-violet light therapy, narrow-band UVB (NB-UVB), 308 nm excimer laser,9 acitretin, cyclosporine, methotrexate, allopurinol, doxycycline, high-dose penicillin and compound glycyrrhizin tablets have been successfully reported. At the same time, effective treatment of combined systemic diseases is critical to the prognosis of acquired RPC.
. Kim SW, Kim MS, Lee JH, et al A clinicopathologic study of thirty cases of acquired perforating dermatosis in Korea. Ann Dermatol 2014;26(2):162–171. doi:10.5021/ad.2014.26.2.162.
. Verma R, Vasudevan B, Pragasam V, et al A rare case of familial reactive perforating collagenosis. Indian J Dermatol 2013;58(5):408. doi:10.4103/0019-5154.117341.
. Gambichler T, Birkner L, Stücker M, et al Up-regulation of transforming growth factor-beta3 and extracellular matrix proteins in acquired reactive perforating collagenosis. J Am Acad Dermatol 2009;60(3):463–469. doi:10.1016/j.jaad.2008.06.006.
. Kikuchi N, Ohtsuka M, Yamamoto T. Acquired reactive perforating collagenosis: a rare association with dermatomyositis. Acta Dermatol Venereol 2013;93(6):735–736. doi:10.2340/00015555-1562.
. Bhat Y, Manzoor S, Qayoom S, et al Familial reactive perforating collagenosis. Indian J Dermatol 2009;54(4):334–337. doi:10.4103/0019-5154.57608.
. Ohashi T, Yamamoto T. Acquired reactive perforating collagenosis associated with systemic lupus erythematosus. J Dermatol 2016;43(9):1097–1099. doi:10.1111/1346-8138.13357.
. Yazdi S, Saadat P, Young S, et al Acquired reactive perforating collagenosis associated with papillary thyroid carcinoma: a paraneoplastic phenomenon? Clin Exp Dermatol 2010;35(2):152–155. doi:10.1111/j.1365-2230.2009.03211.x.
. Randie H, Kim, Maryann K, et al Giant Acquired reactive perforating collagenosis in a patient with diabetes mellitus and metastatic breast carcinoma. JAAD Case Rep 2016;2(1):22–24. doi:10.1016/j.jdcr.2015.11.013.
. Matsui A, Nakano H, Aizu T, et al Treatment of acquired reactive perforating collagenosis with 308-nm excimer laser. Clin Exp Dermatol 2016;41(7):820–821. doi:10.1111/ced.12891.