Agminated Fibroblastic Conective Tissue Nevus: A New Clinical Presentation

Abstract

Connective tissue nevi are benign hamartomatous lesions in which one or several of the components of the dermis (collagen, elastin, glicosaminoglycans) show predominance or depletion. Recently, de Feraudy et al broadened the spectrum of connective tissue nevus, describing fibroblastic connective tissue nevus (FCTN), which is characterized by proliferation of CD34+ cells of fibroblastic and myofibroblastic lineage. Only solitary papules and nodules have been described. We present the first case of FCTN with multiple agminated lesions on the leg of an infant and the difficulties encountered in the differential diagnosis with dermatofibrosarcoma protuberans.

Congenital fibroblastic connective tissue nevi: Unusual and misleading presentations in three infantile cases

“…In patient 1 there was an uncommon infiltration of the entire thickness of the subcutis with focal infiltration of the periosteum, which has never been reported. In patients 1 and 2, we report a superficial infiltration into the subcutis; this infiltration is also reported in 31 (67%) cases from the literature . In addition to CD34 positivity of the fibroblastic lineage, all other markers for spindle cells such as S100P, SMA, desmin, and myogenin were negative, except for a moderate focal SMA positivity in patient 3.…”

“…The overlying epidermis was normal histologically in all the cases we report, as opposed to the papillomatous epidermic pattern described in several cases . As in all cases reported (n = 46) in the literature, we did not find cellular atypias or mitoses; adnexal structures were entrapped but always spared . In patient 1 there was an uncommon infiltration of the entire thickness of the subcutis with focal infiltration of the periosteum, which has never been reported.…”

“…In the second largest series available in the literature (14 patients), age ranged from 1 to 56 years . Other smaller series and case reports have described patients at various ages: one case at 1 month old; one case at 5 months old; one case at 9 years old; three cases at 10, 24, and 32 years old; and one case at 15 years old . FCTN may be more frequent in women (n = 25 cases) than men (n = 20 cases) …”

“…FCTN are difficult to diagnose because of their clinical heterogeneity . Congenital FCTN have rarely been reported .…”

Agminated fibroblastic connective tissue nevus in a 1‐year‐old boy

“…Bouaoud et al reported congenital FCTN in three infants with unusual features that were suggestive of sarcoma, lipoma, and vascular malformation. In 2016, Downey et al first reported a unique case of FCTN with multiple agminated lesions on the right lower leg of a 5‐month‐old boy, which was diagnosed as agminated FCTN. Although FCTN is typically a solitary lesion, agminated variants should be kept in mind.…”