Subungual pleomorphic fibroma

Pleomorphic Onychomatricoma: A Mimicker of Malignancy

Pleomorphic onychomatricoma is a rare condition mimicking malignant neoplasms. Given its rarity, the diagnostic and prognostic criteria of this condition are not well established. The aim of this study was to characterize a series of 6 cases of pleomorphic onychomatricoma. In 3 cases the submitting clinical diagnosis was subungual squamous cell carcinoma. For all 6 cases, nail clipping showed typical features of onychomatricoma as a free-edge thickening and pitting of the nail plate with an additional feature of projecting line pattern. Pleomorphic onychomatricoma was diagnosed based on moderate-severe cytological atypia, yet degenerative-appearing with multinucleation or smudged chromatin, no mitotic activity or necrosis, and a Ki67 proliferative index inferior to 5% overall. Other finding s included epithelioid multinucleated cells with deeply eosinophilic cytoplasm mimicking epithelioid malignant cells, overexpression of Ki67 and p53 on atypical cells and diffuse expression of p16. This study describes additional criteria in pleomorphic onychomatricoma, permitting a wider recognition in order to avoid inappropriate treatment.

Myxoid Onychomatricoma-A New Case

Onychomatricoma is a slow-growing, benign neoplasm of the nail matrix with several histological variants. With only 2 cases previously reported, the term "myxoid onychomatricoma" has been used by some authors to describe a rare variant, known to have a fibromixoid component. We present a case of a 51-year-old Caucasian woman with a 1-year history of thickening and discoloration of the right thumbnail, who was initially misdiagnosed as onychomycosis. After performing a magnetic resonance imaging that showed a tumor with several filamentous projections, an onychomatricoma was suspected and a total distal plaque avulsion was performed. Histology revealed a biphasic tumor with an epithelial component and a prominent myxoid stroma. Immunohistochemical staining was then used, confirming the diagnosis. Considering these findings, we believe that our case meets the diagnostic description of "myxoid onychomatricoma" and is, therefore, a new case of this rare histological variant.

Pleomorphic fibroma of the skin with MDM2 immunoreactivity: A potential diagnostic pitfall

Pleomorphic fibroma is a rare benign cutaneous neoplasm characterized by spindle-shaped cells and multinucleated giant cells scattered throughout collagenous stroma. These morphologic features can lead to diagnostic confusion, including atypical lipomatous tumor as one consideration. In contrast to atypical lipomatous tumor, previous studies have found pleomorphic fibroma to be negative for MDM2 immunohistochemical staining and MDM2 gene amplification. Here, we present a case of pleomorphic fibroma of skin with nuclear MDM2 immunoreactivity in the absence of MDM2 gene amplification, underscoring the superiority of fluorescence in situ hybridization as a diagnostic test in this differential diagnosis. The RB1 locus is also explored for differential diagnosis with pleomorphic/spindle cell lipoma and related entities.

Cytomorphology of pleomorphic fibroma of skin: A diagnostic enigma

Pleomorphic fibroma (PF) is a benign, polypoid, or dome-shaped cutaneous neoplasm with cytologically atypical fibrohistiocytic cells. We describe the cytomorphological features of PF retrospectively with histopathological diagnosis in a 38-year-old male who presented with 3 × 1.5 cm swelling in the soft tissues of the thigh for 6 months. This lesion is benign despite the presence of pleomorphic or bizarre cells. We review the differential diagnosis of PF with other mesenchymal tumors. To the best of our knowledge, cytomorphological features on fine needle aspiration cytology of this tumor are not yet documented in literature.

Benign subungual tumors

A variety of benign and malignant processes may affect the subungual region; however, most are relatively rare lesions. We present a review of the current literature regarding benign tumors affecting the subungual region.