Plexiform fibrohistiocytic tumor on the chest of a 5‐year‐old child and review of the literature

Abstract

A 5-year-old, otherwise healthy, female presented to the dermatology clinic with a 1-year history of a raised lesion on her right upper chest ( Figure 1). Her parents originally believed it was a mosquito bite; however, it continued to enlarge over time. While occasionally tender, no bleeding, crusting, or discharge from this solitary lesion was reported.Physical examination revealed a 2.0-cm by 1.5-cm rubbery, smooth, mobile tumor with overlying telangiectasias and erythema on the right chest. The tumor was nontender; neither tent sign nor punctum was visible. A skin biopsy and subsequent excision revealed a well-demarcated dermal tumor composed of mononuclear histiocytes and osteoclast-like giant cells arranged in a plexiform pattern on hematoxylin and eosin (H&E)-stained sections. (Figure 2A).Throughout the specimen, no necrosis or cellular pleomorphism was appreciated ( Figure 2B). The lesional cells were highlighted with vimentin and CD68 ( Figure 2C). MITF, S-100, and pancytokeratin stains were negative. Smooth muscle actin highlighted small vascular channels but was negative in the lesional cells. Between the plexifom collections of histocytes, a collagen stroma was noted, which showed some areas of sclerosis. These features established the diagnosis of plexiform fibrohistiocytic tumor. In the excisional specimen, the tumor extended to the margins, and re-excision did not show any residual lesion. | ME THODSA review of previously published literature was performed to identify case reports, case series, reviews, and retrospective studies that described novel cases of plexiform fibrohistiocytic tumor (PFT).Using the National Center for Biotechnology Information PubMed tool, the search was narrowed using the key terms of "plexiform," "fibrohistiocytic," and "tumor." The inclusion criteria included the aforementioned study types whose individual cases demonstrated histologic evidence of PFT diagnosis, namely histiocytes and giant cells arranged in a plexiform pattern of dermal tumor nodules.Exclusion criteria included studies published in a language other than English and lack of appropriate histologic diagnostic features.Tumors occurring in adults were included as well for completeness. AbstractPlexiform fibrohistiocytic tumor (PFT) is a rare neoplasm of mesenchymal origin that can be identified by its propensity for children and adolescents combined with a characteristic histologic arrangement of histiocytes and osteoclast-like giant cells whorled within tumor islands. A 5-year-old female presented with a raised, intermittently tender, and slowly enlarging tumor on her chest, which was histologically confirmed to be a PFT. We present this case along with a comprehensive review of PFT cases reported in the literature to describe the demographic, histologic, and rarely metastatic behavior of this entity. It is important to include PFT on the differential diagnosis of an enlarging tumor in the pediatric population. K E Y W O R D Sdermatopathology, lumps/bumps, neoplasms-benign

Solitary nodule on the shoulder of an 11-year-old child

“…A congenital origin has been described in only very few patients [3][4][5]. Despite a female prevalence being initially suggested, recent studies demonstrate a similar distribution between genders [2][3][4].…”

“…Since the first description of this distinct neoplasm in 1988, about 200 cases have been reported in the literature. Although its age of presentation ranges from two months to 77 years [2,3], PFHT shows a distinct predilection for children and young adults, with 70% of cases occurring in individuals under 20 years of age [3]. A congenital origin has been described in only very few patients [3][4][5].…”

“…It clinically presents as a painless, solitary, slowgrowing dermal or subcutaneous nodule [1][2][3][4][5][6] or, less frequently, as a firm, indurated plaque [4][5][6]. In rare instances, ulceration can develop [4].…”

“…Diagnosis relies primarily on the unique histopathological pattern of PFHT [2]. The neoplasm is typically located in the deep dermis, with possible extension to the hypodermis and other deeper subcutaneous layers [6].…”

“…Regional lymph node metastases have been reported in 2.4% of cases. Despite its rarity, distant dissemination to the lungs has also been described in 1.9% of patients [2], having resulted in one fatal outcome [4]. At present, no clinical or histopathological features of PFHT can reliably correlate with its behavior and metastatic capacity [1,5,6].…”