Abstract
Angiosarcoma and its epithelioid variant are vascular malignancies that rarely affect the facial skeleton. Epithelioid angiosarcoma resembles carcinoma and can be difficult to diagnose. A case is presented of metastatic epithelioid angiosarcoma to the mandible from an angiosarcomatoid portion of renal carcinoma. The diagnostic challenge is outlined and the literature is reviewed.
Angiosarcoma, a mesenchymal malignancy of vascular origin, makes up less than 1% of sarcomas. The rare epithelioid variant of angiosarcoma is often high-grade, aggressive, and presents with early metastasis. This variant has been reported to occur in the skin, deep soft tissue, thyroid, adrenal glands, and spleen, as well as the axial and appendicular skeleton. One case of epithelioid angiosarcoma (EA) has been reported in the maxilla and is the only reported case involving the facial skeleton. EA is a diagnostic challenge given its rarity and its resemblance to carcinomas. We report an unusual case of metastatic mandibular EA occupying the condyle and infratemporal fossa from an angiosarcomatoid portion of renal cell carcinoma.
Case report
A 64-year-old man was referred for management of a mass associated with the right mandibular condyle and medial soft tissue. He was diagnosed with renal cell carcinoma (Fuhrman grade IV, with clear-cell and sarcomatoid features) of the right kidney metastatic to the right shoulder 9 years prior to presentation. After a right nephrectomy and composite scapular resection, he underwent postoperative chemotherapy. His medical history was also notable for type II diabetes mellitus, hypertension, morbid obesity, obstructive sleep apnea, and diverticulitis requiring a partial colectomy.
The patient remained in remission until he developed pain in the right temporomandibular joint (TMJ) and a change in his occlusion. A positron emission tomography (PET) scan revealed increased uptake in the right mandibular condyle ( Fig. 1 A). A computed tomography (CT) scan showed a poorly defined radiolucency involving the medial condyle and sigmoid notch of the mandible. The mass extended into the lateral pterygoid muscle and infratemporal fossa ( Fig. 1 B). Magnetic resonance imaging showed a 2 cm × 3 cm × 2 cm multilobulated mass within the medial aspect of the right TMJ, with erosion of the medial and central aspect of the right condyle ( Fig. 1 C). Core biopsies showed bone and dense collagenous tissue with reactive changes; there were no malignant cells. The patient was referred to our institution for further diagnosis and management.
Upon presentation, the patient complained of a dull, constant pain in the right preauricular area; however, he had full mandibular opening (maximal incisal opening = 45 mm). No mass was palpable extra- or intraorally. The pain did not increase with palpation. He had a malocclusion characterized by a right posterior open bite. His mandible deviated to the left on opening. His cranial nerve examination was normal. There was no cervical or submandibular lymphadenopathy. An otoscopic exam revealed a normal external auditory canal and tympanic membrane. The patient was presented to the University of California, San Francisco multidisciplinary head and neck tumour board. Based on his worsening symptoms, history of renal cell carcinoma, and the need for a definitive diagnosis, a resection was recommended. A transcervical approach was used to access the right mandibular ramus–condyle unit and infratemporal fossa. The condyle was found to be expanded and abnormal. The planned osteotomy was approximately 1.5 cm inferior to the tumour. The mandibular condyle was disarticulated while preserving the condylar disk. The involved lateral pterygoid muscle was resected. A margin consisting of normal soft tissue, bone, and muscle was resected with the specimen. The resected specimen measured 5.5 cm × 3.5 cm × 2.0 cm with a 2.2 cm, firm, smooth, circumscribed, red-brown nodule protruding from the medial surface of the condyle and ramus ( Fig. 2 ). The distance from the nodule to the resection margin was 2 cm and there was no violation of tumour. A 2.4-mm reconstruction plate with a condylar prosthesis was used for reconstruction. There were no intraoperative complications.
Histopathology revealed a multinodular proliferation of large pleomorphic and atypical polygonal cells with multilobulated and mitotically active nuclei, as well as spindled cells. Most of the tumour cells had cytoplasm that was abundant and eosinophilic; however, cells with clear cytoplasm were also present ( Fig. 3 ).
The vascular background consisted of dense capillaries amongst tumour cells; medium and large vessels were adjacent to the tumour nodules. Given the pleomorphic and atypical cells with a high degree of mitotic activity, a malignant proliferation was assured and the differential diagnosis included metastatic renal cell carcinoma, melanoma, and epithelioid sarcoma. Immunohistochemistry was positive for keratin, epithelial membrane antigen (EMA), CD10, CD31, Friend leukaemia virus integration 1 (FLI-1), and Factor VIII-related antigen (Factor VIII RAg) ( Fig. 4 A–D). There was no expression of renal cell carcinoma (RCC) antigen, paired box gene 2 (PAX-2), S-100, human melanoma black 45 (HMB45), or CD34. Integrase interactor 1 (INI-1) expression was not abnormally increased.
