Pleomorphic adenoma is the most common type of salivary gland tumor and the most common tumor of the parotid gland. Because of its propensity for invasion, pleomorphic adenoma of the parotid requires superficial parotidectomy or total parotidectomy to minimize the risk of tumor recurrence. We report a case of pleomorphic adenoma of the parotid gland with repeated recurrences. A 23-year-old male patient presented with a protruding neck mass. Six years prior to this presentation, the patient had undergone superficial parotidectomy for the removal of pleomorphic adenoma of the right parotid gland at our institution. The patient experienced recurrence at 17 months after the initial resection, which required a total parotidectomy with partial resection of the facial nerve. Pathologic examination revealed histologic findings consistent with pleomorphic adenoma across the surgical specimen from all three of the operations. The patient suffered from facial nerve paralysis, with facial expressions partially recovered over a year.
Pleomorphic adenoma is the most common tumor of the parotid gland. Enucleation alone is associated with high recurrence rates (8%–45%), owing to the invasive histopathologic characteristics of the tumor. In contrast, total parotidectomy is associated with a much lower rate of recurrence at 0.4% [
The present report describes a case of pleomorphic adenoma that recurred twice.
A 23-year-old male patient presented with a protruding neck mass. Six years prior to this presentation, the patient had undergone superficial parotidectomy for the removal of pleomorphic adenoma of the right parotid gland at our institution (
At physical examination, the 1.5 cm mass was located within the surgical scar on the upper portion of the sternocleidomastoid muscle. It was firm, indolent, and nontender. Computed tomography (CT) scan of the neck revealed a 5.1×3.2-cm multinodular mass at the site of initial tumor location, along the 1.5-cm subcutaneous mass in the surgical scar area (
Under general anesthesia, the mass was excised with wide margins. At the site of cervical surgery scar, the mass was located in the subcutaneous layer and surrounded by fibrotic tissue, but no glandular tissue was observed. The multinodular mass deeply rooted in the trunk of facial nerve and expanded beyond the area occupied by the first tumor. Intraoperative frozen section confirmed both masses having benign histology. Therefore, both masses were resected along with all surrounding scar tissues. A portion of the frontal branch of facial nerve were sacrificed for complete resection of the parotid mass.
Histopathologic examination of the initial resection demonstrated solitary nodules containing a mixture of epithelial and mesenchymal structures. It was a typical pleomorphic adenoma with tubular or linear architecture of epithelial cells and hyaline and myxochondroid appearance of stromal components. Tissues obtained after the second surgery also comprised multiple nodules. Histopathologic findings indicated that the recurrent tumor was also a typical pleomorphic adenoma but composed of more than 80 large and small nodules. We observed both the presence of microscopic extensions or pseudopodia—finger-like expansions—protruding beyond pseudocapsule and capsular penetration. Tissues obtained after the third operation, conducted five years following the second, consisted of more than 50 nodules, similar to that in the tissues collected after the second surgery. Histologic findings were identical for surgical specimen from initial, second, and third operation - except that one of the nodules contained mostly epithelial cells with high cellularity and few mitotic figures (1 mitotic figure per 10 high power fields) (
Pleomorphic adenoma is the most common benign tumor of the parotid gland. Most instances of the adenoma occur in individuals between 30 and 60 years of age, with a predilection for the female sex. Histologically, the tumor consists of epithelial and mesenchymal cells, but various patterns may be present in any given tumor [
Pleomorphic adenoma is characterized by the presence of microscopic extensions protruding beyond pseudocapsule or by capsular penetration. Simple enucleation of pleomorphic adenoma is associated with high recurrence rates, between 8% and 45%, which is reduced to less than 5% with superficial parotidectomy and further down to 0.4% with total parotidectomy [
Pleomorphic adenoma of the parotid gland usually presents as a single mass at initial presentation. In contrast, recurrent masses present as multinodular lesion in 33%–98% of cases. Recurrent tumors usually appear near the surgical scar from previous resection. Recurrence rates do not vary according to age or gender. An incomplete resection of adenoma could be due to capsular penetration that leads to the spread of tumor cells or to the existence of satellite lesions surrounding the capsule. One strategy to reduce the rate of recurrence is to re-evaluate surgical margins using intraoperative frozen sections. In addition, the optimal regimen should involve total parotidectomy, rather than enucleation or superficial parotidectomy [
Zernial et al. [
Although complete resection of the parotid gland decreases the risk of recurrence, the major disadvantage is with the potential complication for facial nerve damage. Scarring of the surrounding tissues results in anatomical changes that make it difficult to distinguish between tumor and normal tissue. In many cases, the facial nerve is surrounded by scar tissue [
Radiation therapy may be an option for postoperative treatment of recurrent pleomorphic adenoma, especially for cases in which multinodular masses were present, multiple recurrences have occurred, facial nerves must be sacrificed, or complete excision is practically difficult. However, no strong evidence exists for efficacy of radiation therapy, and some authors have suggested that radiation therapy should be kept as the last resort management of malignant transformation [
The patient experienced repeated recurrence of pleomorphic adenoma despite multiple resections. Because of the adhesion between the tumor and facial nerve, the patient suffered from postoperative facial nerve damage. However, we observed only minor facial nerve weakening at 18-month follow-up. While multiple recurrence of pleomorphic adenoma has been reported elsewhere, our patient represents the first report of such a case in the Korean population [
No potential conflict of interest relevant to this article was reported.