Recurrent pleomorphic adenoma of the parotid gland with cervical metastasis

Maxillofacial diagnostic features of the enigmatic metastasizing pleomorphic adenoma

Considering the confusion in the literature regarding local recurrence, spread, or metastases of pleomorphic adenoma (PA) in the head and neck region, the aim of this study was to enhance understanding of the characteristics of metastasizing pleomorphic adenoma (MPA) by reviewing the literature and presenting a case. English language articles with proof of metastases were included in the literature review. Of the 80 cases in the literature with MPA, 46 were female and 33 were male (sex missing for one case). Thirty-five percent of the neoplasms affected the bones; the maxilla was affected in five cases and the mandible in three. The parotid was the primary site in 72.5% of cases and the submandibular gland in 16.2% of cases. The local recurrence rate was 70%. The mean interval between primary PA and MPA was 15.52 years. The total mortality rate was 8.7%. A case of PA of the submandibular gland that recurred after surgical excision and metastasized (confirmed by the presence of intact cortical borders) to the ipsilateral mandibular body, upper lip, and neck is described. The high mortality rate in a histologically defined benign disease that metastasizes demands that management include careful primary excision and long-term clinical follow-up.

[Carcinoma ex pleomorphic adenoma of major salivary glands--a clinicopathologic review]

BACKGROUND

Pleomorphic adenoma (PA) is the most common neoplasm of the major salivary glands. There are three subtypes of malignant PA: carcinoma ex pleomorphic adenoma (CXPA); carcinosarcoma (true malignant mixed tumor) and metastasizing pleomorphic adenoma. The most common subtype of malignant PA is CXPA which develops in primary or recurrent PA. For proper diagnosis of CXPA, a statement of coexistence of pleomorphic adenoma and carcinoma (or carcinoma after prior PA surgery) is needed. Own material is presented because of rarity and clinicopathologic specificity of this neoplasm.

METHODS

Retrospective analysis of the medical data of 19 patients who were treated at our department because of CXPA from 1990 to 2002 was done. The following clinical factors were evaluated: age, sex, symptoms (time of lasting, evolution), tumor size, invasion of the adjacent structures and facial nerve, neck nodes, clinical stage, treatment outcome. One pathologist reviewed histological material of 18 out of 19 patients who had been operated and pathological factors such as sensitivity and accuracy of fine needle aspiration biopsy, grade, histology and proportion of malignant component in tumor, lymph nodes metastases were analyzed.

RESULTS

There were 11 men and 8 women, the mean age was 57 years. In 15 cases, tumor was localized in the parotid and in 4 in the submandibular gland. Two patients had history of prior surgery of PA. Duration of symptoms of benign PA was from 2 to 40 years (mean 17.8 years). Symptoms of malignant transformation occurred in 15 patients, the most common were rapid enlargement of tumor, pain and facial nerve palsy. Tumor size varied from 2 to 20 cm with a mean of 6 cm. In 14 patients, the neck was evaluated clinically as No, in 5, examination identified enlarged lymph nodes. Adjacent structures were invaded by neoplasm in 5 cases. Sensitivity and accuracy of fine needle aspiration biopsy in detection of malignant character of PA were 60% and 46% respectively. 17 out of 18 tumors reviewed by the pathologist were high grade. Only in 6 patients, proportion of carcinoma in the mass was less than 50%. The most common malignant component in CXPA was adenocarcinoma (9 cases) and undifferentiated carcinoma (6 cases). Pathologic examination showed metastases to the lymph nodes in 7 out of 10 patients with prior neck dissection. 16 patients were treated surgically (12 of them had also radiation therapy) and 3 patients underwent only (chemo)radiotherapy. Determinate survival at 5 years was 73.6% and in the group treated surgically (alone or with postoperative irradiation) 87.5%.

CONCLUSIONS

Malignant transformation of PA occurs in 5 to 25% untreated patients, usually after 15-20 years and warning symptoms are present in the most cases. Fine needle aspiration biopsy has insufficient sensibility and accuracy in detection of malignant character of PA. Clinical picture and histopathological examination determinate the diagnosis of CXPA. Proper histological classification of malignant component can be found difficult. Surgical treatment (alone or with postoperative irradiation), if possible, allows to achieve good locoregional control of CXPA. 5-years survival varied between 30 to 76%. The best method of prevention and treatment of CXPA is early and radical removal of all major salivary glands tumors.

[Metastasis of a pleomorphic adenoma]

OBSERVATION

A 53-year-old man underwent a right parotidectomy in 1993 for a pleomorphic adenoma. The tumor relapsed locally, three years later, imposing a reoperation. The histology was unchanged. Two years later, the excision of a new local recurrence revealed a histological evolution with intravascular emboli, some cellular atypia and some mitoses. One year later, in a context of cephalgia and amaurosis, metastases were discovered on the calvarial skull. These were treated by radiotherapy. The patient died of a cerebral hemorrhage related to a history of familial autoimmune thrombocytopenia.

DISCUSSION

Regional and systemic metastases of pleomorphic adenomas are exceptional. The local recurrence is characteristic of metastatic forms of pleomorphic adenomas; it occurs in 90% of the cases. No clinical or histological criterion allows distinguishing between recurrent metastatic forms and non-recurrent metastatic pleomorphic adenomas. The metastatic mechanism is not clearly elucidated yet. The best treatment for metastases of a pleomorphic adenoma is surgical excision. The recurrence after a complete surgical excision is rare and the prognosis excellent.

Metastasising pleomorphic adenoma of the parotid gland

A 33-year-old man had a left superficial parotidectomy for a pleomorphic adenoma. He remained well, but 28 years later developed a metastasis in a lymph node in the left supraclavicular fossa.