Desmoplastic fibroblastoma (collagenous fibroma) on the mandibular ridge: case report and review of immunohistochemical markers

The desmoplastic fibroblastoma (DF) is a rare benign soft-tissue tumor of fibroblastic and myofibroblastic origin, and its occurrence in the oral cavity is rare. This study details a new case of an elevated lesion in the alveolar ridge of a 59-year-old woman, painful during mastication. The histopathological exam showed non-encapsulated stellate-to-spindle cells proliferation in a hypocellular collagen-rich stroma. Tumor cells were strongly and diffusely positive for vimentin, and some cells were focally positive for α-smooth muscle actin, CD99, and β-catenin. The exams were conclusive for DF diagnosis. The patient is in the follow-up period, and no recurrent lesions were detected within one year. Despite having similar clinical, pathological, and immunohistochemical features to the cases previously described, the DF in this report is at an unusual oral site and associated with painful symptomatology. Immunohistochemistry is an important tool in DF cases where the histopathological examination is not conclusive.

A desmoplastic fibroblastoma that developed in the anterior mediastinum: a case report

Background Desmoplastic fibroblastoma (also known as collagenous fibroma) is a benign, slowly growing soft-tissue tumor. Most desmoplastic fibroblastomas develop in the limbs, neck, or trunk. A mediastinal origin is quite rare. Case presentation A 32-year-old Asian female was referred to us for the diagnosis and treatment of an anterior mediastinal tumor. The tumor was 80 mm in the largest diameter and was located on the pericardium. No invasion was evident. She underwent resection of the tumor via video-assisted thoracoscopic resection. The tumor was totally encapsulated, and its pedicle was on the pericardium. The resected specimen was very rigid, making it difficult to remove from the intercostal space. Histologically, the tumor was composed of a paucicellular dense collagenous tissue. Mitosis was rarely observed, and cellular atypia was not evident, suggesting that the tumor was benign. We diagnosed the tumor as a desmoplastic fibroblastoma by morphology and immunohistochemistry. Conclusions Desmoplastic fibroblastoma of the mediastinum is an extremely rare disease. Preoperative diagnosis is difficult. Early surgical resection is suitable for diagnosis and treatment planning.

An extremely rare case of desmoplastic fibroblastoma exhibiting rapid growth in the chest wall: a case report

Background Desmoplastic fibroblastoma is an uncommon, benign, fibrous tumor exhibiting infiltrative growth. Most of these tumors are small, slow-growing, and develop as subcutaneous lesions in the extremities. Cases of desmoplastic fibroblastoma in the chest wall are quite rare, and the preoperative diagnosis of such cases remains challenging as these tumors can mimic the characteristics of desmoid-type fibromatosis, which often occurs in the chest wall. We aimed to describe a rare case of desmoplastic fibroblastoma exhibiting rapid growth in the chest wall of a patient that was successfully treated with marginal excision only by diagnostic imaging before surgery. Case presentation A 79-year-old man was admitted to our hospital after experiencing right shoulder pain lasting for a few months. A 4 × 4 × 2 cm mass was incidentally detected at the right second rib two years prior. Chest computed tomography revealed a well-defined homogeneous mass with a muscle-like density along the right lateral chest wall, the size of which had increased to 12 × 10 × 4.5 cm in two years. Dynamic contrast-enhanced computed tomography revealed abundant vascularity at the periphery of the tumor. Magnetic resonance imaging revealed iso-intensity to muscle on T1-weighted images, slightly high intensity on T2-weighted images, and rim-like contrast enhancement at the periphery of the tumor, with uniform thickness on gadolinium-enhanced T1-weighted images with fat suppression. Rim-like contrast enhancement is an imaging feature that can distinguish cases of desmoplastic fibroblastoma from desmoid-type fibromatosis. We diagnosed the tumor as desmoplastic fibroblastoma by diagnostic imaging without tissue biopsy. Marginal excision with videoscopic assistance was performed through a small incision. The pathological diagnosis was desmoplastic fibroblastoma. The patient’s postoperative course was uneventful, and his shoulder pain was relieved after the surgery. Conclusions Desmoplastic fibroblastoma in the chest wall is extremely rare, but should be considered in the differential diagnosis when desmoid-type fibromatosis is clinically suspected. Gadolinium-enhanced magnetic resonance imaging is helpful in confirming the differential diagnosis.

A Desmoplastic Fibroblastoma that Developed in the Anterior Mediastinum

Background:Desmoplastic fibroblastoma (also known as collagenous fibroma) is a benign, slowly growing soft tissue tumor. Most desmoplastic fibroblastomas develop in the limbs, neck, or trunk. A mediastinal origin is quite rare.Case presentation:A 32-year-old female was referred to us for the diagnosis and treatment of an anterior mediastinal tumor. The tumor was 80 mm in the largest diameter and was located on the pericardium. No invasion was evident. She underwent resection of the tumor via video-assisted thoracoscopic resection. The tumor was totally encapsulated, and its pedicle was on the pericardium. The resected specimen was very rigid, making it difficult to remove from the intercostal space. Histologically, the tumor was composed of a paucicellular dense collagenous tissue. Mitosis was rarely observed, and cellular atypia was not evident, suggesting that the tumor was benign. We diagnosed the tumor as a desmoplastic fibroblastoma by morphology and immunohistochemistry.Conclusions:Desmoplastic fibroblastoma of the mediastinum is a rare disease. Preoperative diagnosis is difficult. Early surgical resection is suitable for diagnosis and treatment planning.