Primary Leiomyosarcoma of the Submandibular Gland: A Case Report

Mohamed Reda El Ochi; Hafsa Chahdi; Issam Rharrassi; Abderrahman Albouzidi; Mohamed Oukabli

Disclosures

BMC Clin Pathol. 2015;15(22) 

In This Article

Discussion

Primary sarcomas of the salivary glands are rare accounting for 0,3–1,5 % of salivary gland neoplasms and 1,5–2,3 % of malignant salivary tumors.[1] Primary leiomyosarcomas of the head and neck are uncommon representing 3–10 % of leiomyosarcomas[5] and usually occur between 40–50 years old.[6] They arise mainly in the parotid gland and only 5 cases are reported in the submandibular gland in patients aged above 60 years.[1,2,7,8] Tumors with the following criteria are considered primary salivary gland sarcoma: 1) The patient must not have, or have had, a sarcoma elsewhere; 2) a metastasis to the gland from malignancies of the skin or mucosa of the upper aerodigestive tract must be excluded; 3) the gross and microscopic appearances should be consistent with a primary origin, rather than invasion from the adjacent soft tissues; and 4) within the limits of the microscopic study of multiple sections, carcinosarcoma has to be excluded.[9]

Clinical features are not specific with a painless and progressive mass being the most significant finding.[10–12] Radiological investigations allow evaluation of the extent of the tumor and assessment of the regional lymph nodes.[5,13]

Microscopically, leiomyosarcoma shows a proliferation of intersecting fascicles of spindle cells with ample amount of eosinophilic cytoplasm and elongated nuclei with dispersed chromatin.[7] Mitotic rate is superior to 2 mitosis per 10 high-power fields.[5,14] Foci of pleomorphism and/or necrosis can be found.[7] Immunohistochemistry demonstrates positive staining of the tumor cells for smooth muscle actin and H-caldesmon.[15] Desmin can be either positive or negative.[5,14] S-100 protein, CD34, CD31, CD117, and pancytokeratin are generally negative;[15] these findings play an important role in excluding myoepithelioma, sarcomatoid carcinoma, melanoma, metastatic gastrointestinal stromal tumor, and other sarcomas.[5,7,16] However, the main differential diagnosis is metastatic leiomyosarcoma from other malignancies of head and neck sites, soft tissues and uterine corpus; thus, clinical informations and imaging studies are very important.[7]

Staging of leiomyosarcoma of the head and neck includes chest and abdominal computed tomography and bone scintigraphy.[7]

The management is mainly surgical. Complete surgical excision with clear margins is the mainstay of the treatment[7,12] being associated with low local recurrence and longer survival.[7] Lymph node metastases are exceptional in sarcomas so that lymphadenectomy is not indicated.[7] Adjuvant radiotherapy is recommended for high grade sarcoma, large tumour, and close or positive surgical margins.[2,10,12,13] Chemotherapy is indicated for patients with inoperable tumors, local recurrence or distant metastases.[2]

The prognosis seems to related to the size (greater or less than 3 cm), grade and site of the tumor and the quality of surgery.[7,9] For major salivary gland, the prognosis is poor.[2,8]

In leiomyosarcoma of the head and neck, the five-year survival is 23 %.[2] Recurrences are frequent and occur in 40–60 % of cases.[5] Metastases are rare and occur mainly in lung, bone and central nervous system.[12]

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