Histopathology of a gingival peripheral ossifying fibroma. Light microscopy using Hematoxylin and Eosin staining shows a dense fibrous stroma with proliferating spindle-shaped fibroblasts arranged in fascicles and whorls, with relatively low mitotic activity and mild chronic inflammatory infiltrate at the periphery. The stroma is intimately associated with scattered mineralized deposits representing a mineralized matrix. Notable mineralization includes dystrophic calcifications, cementum-like material, and small bony trabeculae or lamellar bone, consistent with ossifying changes. In older or healed areas, well-formed lamellar bone or cementum-like tissue is seen within the fibrous matrix. The lesion is typically confined to gingival tissue and may cause surface erosion or ulceration; histology demonstrates a reactive, non-neoplastic process with a fibrous proliferative component and focal calcified masses. The diagnostic significance is that presence of calcified material within a fibrous gingival lesion supports POF diagnosis, distinguishing it from fibroma or pyogenic granuloma. Differential considerations include irritational fibroma, cemento-ossifying fibroma, peripheral odontogenic fibroma, and pyogenic granuloma with calcifications. Clinically, this histology aligns with a gingival mass in the anterior maxilla or mandible, excised as part of periodontal therapy. Therapeutic implications include conservative excision with close follow-up due to potential recurrence. The specimen's micrograph underscores the biphasic pattern: fibrous stroma and mineralized nodules.

This composite image includes intraoperative clinical photographs and histopathological photomicrographs detailing the surgical management and cellular features of a psammomatoid juvenile ossifying fibroma (PsJOF) in a 15-year-old patient. Panels 2a and 2b show an infraorbital surgical approach. Panel 2a demonstrates the exposure of a pale, well-circumscribed, lobulated mass within the infraorbital rim, while panel 2b shows the site post-excision and peripheral ostectomy, revealing the underlying bony anatomy of the orbit. Panels 2c (10x magnification) and 2d (40x magnification) are H&E-stained photomicrographs showing the pathognomonic features of PsJOF. The histology displays a cellular fibrous stroma containing numerous small, spherical, mineralized ossicles. These ossicles resemble psammoma bodies, characterized by a basophilic appearance and distinct concentric lamellation. The combination of clinical findings and characteristic psammomatoid ossicles is essential for differentiating this aggressive fibro-osseous lesion from conventional ossifying fibromas in pediatric oral and maxillofacial pathology.

High-power light microscopy of an oral soft tissue biopsy stained with Hematoxylin and Eosin reveals a lesion consistent with peripheral ossifying fibroma. The overall architecture shows a relatively well-circumscribed, hypocellular to mildly cellular fibrous stroma populated by bland spindle-shaped and ovoid fibroblasts, with sparse mitotic activity and minimal atypia. Intermixed within the fibrous matrix are mineralized bony trabeculae, some of which are woven bone, indicating osteogenic differentiation within the lesion. The lamellar mineralization forms irregular islands that disrupt the uniform fibrous background, aligning with characteristic ossification seen in this entity. Inflammatory cells are limited, and the lesion lacks marked necrosis or malignant features. Vascular channels are present but not prominent, contributing to a vascular but non-aggressive appearance. The combination of a fibrous proliferative process with discrete osseous formation in the gingival/periodontal region is classic for a peripheral ossifying fibroma, a reactive, gingival overgrowth linked to irritation or trauma. Clinically, this histology supports conservative surgical excision with careful curettage to minimize recurrence. Differential considerations include fibroma, pyogenic granuloma, and other ossifying/subosseous lesions, but the presence of bone trabeculae within a fibrous lesion strongly favors peripheral ossifying fibroma. Correlation with clinical findings and radiographic imaging aids definitive diagnosis. Clinical correlation advised.

Imaging modality: Light microscopy of a hematoxylin and eosin (H&E) stained histology section. An oral gingival lesion, consistent with peripheral ossifying fibroma, shows a fibrous connective tissue stroma with osteoid matrix formation. The primary tissue features include bland, spindle-shaped fibroblasts arranged in sweeping fascicles and septa, with minimal atypia and low mitotic activity. Lakes of eosinophilic osteoid or bone-like material are identifiable within the fibrous matrix, sometimes accompanied by calcifications. The lesion exhibits mild chronic inflammatory infiltrate and increased vascularity perithreshold to the stroma. The osteoid matrix indicates osteogenic differentiation and is the key diagnostic feature distinguishing this entity from a simple fibroma. The overall architecture blends reactive fibrous tissue with calcified deposits, supporting a diagnosis of peripheral ossifying fibroma rather than other gingival lesions. Differential considerations include fibroma with calcifications, cemento-ossifying fibroma, pyogenic granuloma, and ossifying fibroma; clinical correlation and radiographic context help refine the impression. Clinically, these lesions arise from the interdental gingiva, predominantly in younger individuals, and are treated by complete surgical excision with removal of the lesion base; recurrence is possible. This image is valuable for dental pathology education and differential diagnostic training, illustrating characteristic fibroblastic proliferation coupled with osteoid formation. For clinical teaching and research.