Abstract
Salivary gland carcinosarcomas contain both malignant epithelial and mesenchymal elements making them a true malignant mixed tumour. They may arise ‘de novo’ or from an existing pleomorphic adenoma and are often difficult to diagnose histologically. Management is by means of radical surgery, but prognosis remains poor. We present a case of this rare tumour seen in a young patient to highlight its aggressive potential.
1
Introduction
Carcinosarcoma are rare biphasic tumours consisting of both carcinomatous and sarcomatous elements, first described by Kirklin et al., in 1951 [ ]. A review of the literature reveals less than 75 published cases and only 12 cases of carcinosarcoma with osteosarcoma as the sarcomatous element [ ]. The mean age of involvement is 55 years with no gender predominance [ ]. Carcinosarcomas in salivary glands are highly aggressive and make up 0.4 % of all malignant salivary neoplasms with 65 % of these affecting the parotid gland [ ]. On presentation, more than 50 % of these show distant metastases to the lung, bone or brain [ ].
The most common salivary gland carcinoma is a mucoepidermoid carcinoma followed by adenoid cystic carcinoma and acinic cell carcinoma. The sarcomatous element can vary from chondrosarcoma, fibrosarcoma, osteosarcoma and rhabdomyosarcoma [ ]. The literature suggests that a ‘de novo’ carcinosarcoma may occur in a salivary gland, however, it most commonly arises within a long-standing or recurrent pleomorphic adenoma [ , ].
2
Case summary
We present a case of a 50-year-old otherwise fit and healthy patient referred to the Oral and Maxillofacial clinic by his general practitioner with a four-week history of a large, painless pre-auricular lump. On clinical examination the mass was felt to be originating from the parotid gland with evidence of parapharyngeal extension; facial nerve function was preserved. Initial investigation via ultrasound and MRI ( Fig. 1 ) confirmed a heterogenous mass (6.5 × 5cm) with a necrotic centre. A fine needle aspirate revealed abundant atypical cells in keeping with a malignancy. A core biopsy taken to characterise this further showed sheets of poorly differentiated, large pleomorphic cells with numerous mitoses and areas of necrosis, favouring a carcinoma. A wide panel of immunohistochemistry (IHC) was performed with positivity for AE1/AE3, CAM5.2 and p63. The proliferation index/MIB-1 was >90 %. A PET-CT showed avid fluorodeoxyglucose (FDG) uptake in the tumour mass but no distant metastases. Within weeks the tumour rapidly progressed resulting in a Grade IV House-Brackman facial palsy and ipsilateral vocal cord palsy confirmed on nasoendoscopy.
Multidisciplinary team meeting (MDT) consensus was to proceed with surgical resection. The patient underwent radical parotidectomy via lip-split mandibulotomy for access which revealed an extensive dumbbell shaped tumour ( Fig. 2 ). A type I modified radical neck dissection was carried out. Following a two-week period of ward-based care supported by enteral nutrition the patient recovered and was discharged home. Adjuvant treatment in the form of radiotherapy was in planning but the patient sadly passed away at home; this was only twelve-weeks after initial presentation and six-weeks following surgery. Post-mortem examination revealed marked pulmonary oedema secondary to widespread pulmonary metastases.
