A rare primary localized extranodal histiocytic sarcoma of oral mucosa: a case report

Abstract

<h3>Background</h3> Histiocytic sarcoma is a rare hematopoietic malignancy which typically involves extranodal sites, mainly of the gastrointestinal tract. Of the small number of reported cases in the head and neck region, only one case was localized to the oral cavity. The disease may present as a solitary lesion or disseminated process secondary to other hematopoietic malignancies. Histopathologically, the tumors can be mistaken for other lymphoprolifera- tive disorders. Immunohistochemistry shows tumor cells expressing one or more of the histiocytic markers CD163, CD68, or lysozyme. Surgery with or without chemotherapy or radiotherapy are the mainstays of treatment. Even though histiocytic sarcoma has clinically aggressive behavior with poor response to therapy, studies show that a subset of the patients with localized disease and small tumor size have more favorable outcome with surgery alone. We present a case with localized extranodal histiocytic sarcoma of oral mucosa. <h3>Case Description</h3> A 31-year-old, fe- male with onemonth duration of a 10 × 8 × 2 mm smooth-surfaced, well circumscribed, firm soft tissue enlargement at buccal vestibule of #11/12. Biopsy shows a diffuse population of pleomorphic cells with atypical mitoses and fine granular cytoplasm within fibrocollagenous connective tissue. Immunohistochemical studies demonstrated tumor cells positive to CD163, CD68, CD45, CD43, CD4, muramidase, SOX10, S100, NSE and vimentin with a diagnosis of his- tiocytic sarcoma. Surgical excision with uninvolved margins was performed. The diagnosis of histiocytic sarcoma was confirmed with hematopathology consultation. There was no evidence of tumor recurrence after 3 months fol- low up. <h3>Conclusion</h3> To the best of our knowledge, this is the second case of primary localized extranodal histiocytic sarcoma of oral cavity. Surgery alone was the treatment modality for our case. However, due to the rarity/limited number of reported cases, treatment outcomes of a localized disease is limited. The treatment protocol may become more evident as newer studies emerge.