The Whartin Tumor is the second most frequent tumor of the parotid gland following pleomorphic adenoma. Among the Whartin tumors, Metaplastic Whartin Tumor (MWT) is rare. In case of a MWT, histo-pathological replacement of oncosytic cells by squamous cells, ruptured epidermoid and lymphoe-pithelial cystic areas, a large necrosis area, fibrosis and granuloma formation may be seen. MWT may display similar clinical characteristics as the malign parotid tumor that causes sialadenitis, abscess formation, skin ulceration, and facial paralysis. Although the histopathogenesis of Metaplastic Whartin Tumors is not exactly known, it is postulated that the histo-pathological processes caused by trauma, infection, or radiotherapy have a role in the formation of these tumors. This case study presents a 48-year-old female patient with a complaint of panicula before her left ear persisting for 5 months. Following a superfacial parotidectomy carried out 3 weeks after the fineneedle aspiration biopsy (FNAB), her pathological assessment was found to be in line with Metaplastic Whartin Tumor. Our case study presents the case of a Metaplastic Whartin Tumor case with a review of literature on the subject, accompanied by radiological and histological analyses.
The Whartin’s tumor is the second most frequent tumor of the parotid gland following pleomorphic adenoma [
For the diagnosis of MWT a microscopic analysis with Hemotoxilin Eosin is generally sufficient. To differentiate between flat-cell and mucoepidermoid carcinoma is of utmost importance since these two might be confused histopathologically [13,14].
A 48-year-old female patient presented to our ear, nose and throat clinic (ENT) with a swelling of panicula that was gradually getting bigger before her left ear persisting for 5 months. Physical examination revealed a mass which was 15 × 20 × 15 mm in size, and was rigid, semi-mobile, and a little sensitive to palpation. The rest of her ENT examination results were normal.
Parotid ultrasonography revealed a hypoechoic solid lesion with smooth borders that was circular in shape, and of 17 × 20 × 20 mm in size having septations and ecogenic solid component in the left parotid superficial lobe was reported. The FNAB showed oncosytic cells with single and three dimensional strata on a hemorrhagic and partly lymphocytic ground (Figures 1 and 2). With this result the patient was pre-diagnosed with Whartin’s tumor.
Three weeks after the FNAB the patient underwent left superficial parotidectomy under general anesthesia. During the procedure it was seen that the mass had partial cystic formations and it was dissected from the tissues surrounding the parotitis with difficulty because of intense fibrosis.
Pathological analysis of the specimen revealed threedimensional solid structures formed by eosinophilic stoplasmal oncosytic structures. In some of the regions of these structures total infarct areas and papillary structures were detected. Further, characteristic squamous metaplasia and intense inflammation were seen in the surrounding tissues (Figures 3-6). As a result of this patho-logical evaluation the patient was diagnosed with Metaplastic Whartin’s Tumor. After surgical therapy, the patient was irradiated with 3 cGy to the parotid region. No complications or relapses occurred during the one year postoperative follow-up period.
FNAB offers a high diagnostic gain in salivary gland lesions and is also a safe, fast, inexpensive, physicianfriendly, and an easily tolerable diagnostic method by patients. The most significant point regarding FNAB’s
diagnostic importance in salivary glands is that it enables the pathologist to have a rate of 96% right diagnosis with its high sensitivity and specifity for all salivary gland tumors [
Malignant salivary gland tumors are histologically labile and structurally complex tumors. Epithelial, nonepithelial tumors, lymphomas, metastatic tumors, and non-neoplastic lesions are the malignant tumors of the salivary gland. This diversity makes it difficult to reach a diagnosis through cytological analysis [
FNAB has been shown to have 5.5% wrong positive
and 2.7% wrong negative rates with parotid masses [
Although the histopathogenesis of Metaplastic Whartin’s Tumors is not exactly known, it is argued that the histopathological processes caused by trauma, infection, or radiotherapy have a role in the formation of these tumors [
Especially the other tumors (hurthle cell adenoma of the thyroid) rich in oncosytic cells and mitochondria have also infarcts and squamous metaplasis of different levels following FNAB as is seen with this tumor [21-25]. Following the FNAB some changes may also take place in the inflammatory process of the tumor mass and the surrounding tissues [
All these changes may be seen in other organs like the lungs, lymph node, and the thyroid besides the salivary glands following the FNAB [22,24,25]. Experimental trials conducted with rats’ parotid tissues demonstrated that inflammatory processes as well as metaplastic changes start to take place in a couple of days when the arteries feeding the parotid are bound [
Squamous metaplasia cannot be seen in every Warthin’s tumor where ischemia and necrosis occur. Moreover, metaplastic epithelium in metaplastic Warthin’s tumor does not have atypical cytological features and infiltrating growth pattern [
Most of the reported cases of malignant transformation in Warthin’s tumor did not show distant metastasis. However, local lymph node metastasis was reported [
Treatment of this tumor is primarily surgical, consisting of adequate excision of the primary site with or without neck dissection [
The present case was diagnosed as having squamous metaplastic changes and intense inflamation, and underwent a superficial parotidectomy without neck dissection. After surgical therapy, the patient was irradiated with 3 cGy to the parotid region. The present case has a negative systemic screening for primary cancer, and no recurrence of the tumor for 1 year. The long-term prognosis of these patients is not clear.
Since there are no studies carried out with large case series regarding the frequency with which the FNAB causes metaplasia in patients with the Whartin’s tumor, it has not been possible to point out to the details of this relation in full extent. It should not be disregarded, however, that all Metaplastic Whartin’s Tumor patients do not have either a history of trauma or a history of FNAB [
In terms of a differential diagnosis, it is also important to direct the attention of the pathologist to the metaplastic changes during the postoperative period with those patients with a history of FNAB who had undergone surgery having been prediagnosed with the Whartin’s tumor and who had difficulties of this kind during the surgery.