We describe a rare case of epithelioid angiosarcoma (AS) arising in the parotid area and discuss its immunohistochemical features and cytological correlation. The patient was a 55-year-old Japanese male, who was aware of increasing swelling in the left parotid to lateral cervical area for 1 month. Clinical diagnosis as a parotid gland cancer was made on basis of imaging study followed by fine needle aspiration cytology, which was interpreted as a high-grade adenocarcinoma. He underwent a radical surgical resection, but died of the residual tumor rapidly growing associated with distant metastases 3 months after surgery. Histologically, the tumor comprised round to ovoid or polygonal tumor cells exhibiting marked pleomorphism and a predominant sheet-like arrangement along with extensive soft tissue invasion. Tumor cells were immunoreactive for CD31 and factor VIII, but negative for CD34. In cytological specimens, tumor cells appeared as isolated single cells and in loosely attached groups or three-dimensional cohesive clusters in the necrotic background. The cells varied in size and shape, and had remarkably enlarged and eccentrically located nuclei with prominent nucleoli. Intracytoplasmic lumen was occasionally recognized. Based on the microscopic and immunohistochemical findings, the present tumor was diagnosed as an epithelioid AS. Epithelioid AS may occasionally arise in the maxillofacial areas and be confused with undifferentiated carcinoma or adenocarcinoma because of epithelioid cytology and unique immunohistochemical profiles such as possible expression of cytokeratins and a lack of CD34. Epithelioid AS should be included in differential diagnoses of high-grade epithelioid malignancies in this region.
Epithelioid angiosarcoma exists in the maxillofacial area.
Undifferentiated/dedifferentiated carcinomas should be ruled out in the parotid area.
Absence of CD34 expression and presence of epithelial markers should be noted.
Cytology could be misinterpreted as a high-grade adenocarcinoma in general.
Angiosarcoma (AS) is a highly aggressive and lethal neoplasm that most commonly arises in the skin and superficial soft tissue [ ], although deep soft tissue and the viscera can be affected [ ]. The scalp is exclusively involved, but involvement of the middle to lower facial region is relatively uncommon [ ]. Although AS of the oral and salivary gland area is extremely rare, Fanburg-Smith et al. collected 29 cases of AS of the oral and salivary gland including four cases in the parotid gland and three submandibular gland cases [ ]. Thereafter, examples of the parotid area have been sporadically reported in the literature [ ].
Epithelioid AS arises in the deep soft tissue [ ], in addition to the skin [ ]. It is an extremely aggressive mesenchymal malignancy characterized by epithelioid morphology and common distant metastasis, and sites of occurrence include the abdomen and other visceral sites such as the lungs, adrenal glands, heart, and thyroid gland, but not parotid gland [ ]. One-half of patients are expected to die within 1 year after diagnosis, and overall survival at 5 years does not exceed 20%.
We describe a case of epithelioid AS arising in the parotid area and discuss its immunohistochemical features and cytological correlation.
The patient was a 55 year-old Japanese male with no medical history of note, who was aware of gradually increased swelling in the left parotid to lateral cervical area for 1 month. He was referred to a regional university hospital after visiting the otolaryngology department of a nearby local general hospital. Clinical diagnosis of a parotid gland cancer was made on the basis of findings in magnetic resonance imaging (MRI) and computed tomography (CT) of the neck revealing an ill-defined and irregular-margined mass lesion, which was measured 5×4cm in the largest dimension and located around the lower pole of the parotid gland terminating to the parapharyngeal space ( Fig. 1 a–c). CT of the lungs could not confirm any metastatic lesion. In addition, following fine needle aspiration cytology (FNAC) was interpreted as “Positive, high-grade adenocarcinoma”. The tumor was classified as cT3N0M0 in accordance with the 8th Edition of Union for International Cancer Control (UICC) TNM classification of malignant tumors at that time.
Then, he underwent a radical parotidectomy by an approach using skin incision from the preauricular to submandibular area associated with resection of the submandibular gland and the surrounding soft tissues, in which tumor invasion was suspected by the imaging. Unlike the others, the mandibular branch of the facial nerve could not be reserved, as it was obviously involved by the tumor in the operation. Although the tumor could not be completely resected because of extensive invasion, upper neck dissection was added, but limited to the superficial area due to too much intraoperative bleeding.
Within a week, the residual tumor rapidly grew and was associated with distant metastasis to the lung, liver and spleen detected by CT the chest and abdomen. Despite post-operative radiotherapy carried out with X-ray dose of 42Gy, which was combined with chemotherapy involving cisplatin of 60mg/m 2 in each course for three times, the patient died of the tumor accompanied by abdominal bleeding, disseminated intravascular coagulation approximately 3 months after surgery in the original hospital. An autopsy was not performed.
Macroscopically, the tumor formed an ill-defined, reddish brown mass located between the parotid and submandibular glands entrapping the cervical soft tissue ( Fig. 1 d).
Histologically, it mainly comprised round to ovoid or polygonal tumor cells exhibiting marked pleomorphism, with spindle-shaped cells intermingled in limited area, and with a sheet-like unstructured arrangement dominating throughout the lesion. Serous acini and skeletal muscle fiber bundles had been destroyed by penetrating tumor cells, and slit-shaped blood vessel-like pattern was noted at the margin of the lesion ( Fig. 2 ). Lymph node metastasis as well as pterygoid muscle invasion was not noted. The tumor was retrospectively classified as pT3N0M0 in accordance with the American Joint Committee on Cancer (AJCC) TNM classification system.