Low-grade gingival leiomyosarcoma in a child.

Leiomyosarcoma (LMS) of the oral cavity, a rare mesenchymal tumor exhibiting smooth-muscle differentiation, is extremely uncommon in childhood. The most frequent location of childhood LMS is the gastrointestinal tract, particularly the stomach. The purpose of this paper is to report a case of leiomyosarcoma affecting the gingival tissues and mandible of a 9-year-old girl with peculiar clinical, microscopic, and radiographic features. Clinical and radiographical examinations revealed a gingival growth affecting the primary mandibular right first molar with inflammatory features. The lesion was initially suspected to be pyogenic granuloma and was removed by excisional biopsy. Microscopic findings showed a hypercellular proliferation of mesenchymal spindle cells, suggesting malignant spindle cell neoplasm. Immunohistochemical, histochemical, and radiographic studies were undertaken, and the final diagnosis established was a low-grade leiomyosarcoma in the gingiva.

Low-grade central osteosarcoma of the mandible: a case study report.

Low-grade central osteosarcoma is a rare type of osteosarcoma with peculiar clinical radiographic and microscopic features. The aim of this article is to report and discuss a case of low-grade central osteosarcoma in the mandible of a 42-year-old woman. The patient reported sensing mild pain and tooth mobility for a period of 4 years, despite continuous dental treatment. Radiographic evaluation showed a mixed radiopaque/radiolucenct lesion in the body, ramus, coronoid process, and condyle of the left side of the mandible. Destruction of the mandibular cortex in the area was also observed. After incisional biopsy, the patient underwent hemimandibulectomy. Microscopic findings showed a tumor exhibiting spindle cells with nuclear hyperchromasia and no mitotic activity, irregular osteoid formation, and soft tissue infiltration. The immunohistochemical analysis of the expression of Ki-67, Cyclin B1, and PCNA proteins (cellular proliferation markers) revealed a very low Ki-67+ and Cyclin B1+ cell index (mean 7% and 3%, respectively), but a moderate number of PCNA+ cells (mean 49%). The 2 years of clinical and imaging postoperative follow-up showed no evidence of recurrence. Clinicians should be aware of these lesions, because histopathologicially low-grade central osteosarcoma may be misinterpreted as fibrous dysplasia.