[Calcifying Aponeurotic Fibroma, a Rare Benign Entity to Consider: a Systematic Review of Literature]

Calcifying aponeurotic Fibroma (CAF) is a benign neoplasm that most commonly onsets in the distal extremities during the childhood. It usually presents as a slow growing non-painful mass. The purpose of this study is to carry out a systematic literature review aimed to delineate the main clinical characteristics of this nosologically entity to define the therapeutic approach and outcome.

A systematic literature review was conducted from March to June 2022 using five major databases: PubMed, Scopus, Embase, MEDLINE, and the Cochrane Library. Studies published in English between 1953 and 2022 reporting clinical cases of Calcifying Aponeurotic Fibroma (CAF) were considered. Eligible studies included case reports and case series; non-English articles, animal studies, and papers lacking sufficient clinical detail were excluded. Two independent reviewers screened the studies following PRISMA guidelines. Extracted data included patient demographics, tumor characteristics, clinical presentation, diagnostic method, treatment strategy, histological findings, clinical outcome, and follow-up duration.

74 papers were identified and 44 were considered relying on their title and content. 125 patients in total,49 females and 76 males have been included. The lesions were clinically presented as an indolent mass, sometimes associated with functional impairment and discomfort; the extremities were the most common localization. The diagnosis was made in 35 cases with a biopsy and in 60 cases it was obtained after the histological examination on the entire operating specimen without doing a preoperative biopsy. In the remaining 30 cases, there was no information about biopsy or histological examination. A total amount of 91 cases were surgically treated with wide excision and 68 of those had regular follow-up. The mean follow-up was 46.2 months, and local recurrence was observed in 20 cases of 68 (29.4%).

Calcifying Aponeurotic Fibroma is a rare benign tumor, typically arising in the distal extremities of children and young adults. Although often indolent, it can exhibit locally aggressive behavior and recur after excision. Atypical sites and extensive forms suggest a broader clinical spectrum than previously recognized. Imaging aids diagnosis, but histological confirmation is essential due to overlap with other pediatric fibromatoses. The tumor shows myofibroblastic differentiation, frequent calcification, and occasional cartilage formation. While wide excision remains the preferred treatment to reduce recurrence, conservative surgery may be considered to preserve function in sensitive locations. Malignant transformation appears anecdotal and unconfirmed.

CAF has been found to be a benign disease that affects both genders with similar frequency; it is rare even if it is probably underestimated. Surgical treatment should be as extensive as possible in order to reduce the risk of local recurrence. Further researches are however necessary to support the evidence provided by this first literature review.