Pathologic findings:
Consists of multiple fragments of fleshy brownish tissues measuring
4.5 cm in aggregate dimension. Sections show multiple fragments of tumour
tissues which are mostly poorly differentiated in nature. These consist
of large solid groups of cytologically malignant epithelial cells surrounded
by an oedematous stroma. These cell show marked nuclear pleomorphism and
a high mitotic rate. Focal necrosis and calcification are noted. Groups
of poorly formed glandular lumen are also seen, indicating an adenocarcinoma.
However, in at least one fragment, evidence of an underlying benign tumour
with features of a pleomorphic adenoma are also found. This fragment consists
of rather bland tumour cells with little pleomorphism. These cells are
arranged into sheets separated by a myxoid stroma similar to those of pleomorphic
adenoma. Some fragments also include the residual respiratory epithelium
and the nasal mucosa containing some mucus glands.
| Figure 1: Benign area | Figure 2: Benign area | Figure 3: Benign area |
| Figure 4: Mixed area | Figure 5: Mixed area | Figure 6: Mixed area |
| Figure 7: Malignant area | Figure 8: Malignant area | Figure 9: Malignant area |
Pathologic Diagnosis:
Mass from nasal septum - Poorly differentiated adenocarcinoma, probably arising from malignant change in a pleomorphic adenoma.
Pathologist Comments:
Adenocarcinoma of the nasal cavity and paranasal sinuses could be of one of two types: Those without a specific salivary gland pattern usually arises on the middle turbinate or in the ethmoid sinus. These are believed to arise from the mucosal lining rather than the subjacent glands. Most of these tumours are well differentiated.
This patient's tumour probably is of the second type of adenocarcinoma which has a salivary gland pattern. The tumour in this patient, although anaplastic in most areas, has features of an underlying pleomorphic adenoma (benign mixed tumour) suggesting an origin from minor salivary glands. The relative frequency of salivary type tumours is similar to the density and distribution of the sero-mucous glands in the area. Hence, they have a predilection for the nasal septum and turbinates or ostial regions. In the nasal cavity, there is a relatively high proportion of benign tumours (benign mixed tumour). The large majority arise from the mucosa of the bony or cartilaginous septum. However, nearly all types of salivary gland tumours have been reported in the sinonasal region. In contrast to the nasal cavity, most tumours in the paranasal sinuses are malignant, adenoid cystic carcinoma being the most common.
The recurrence rate of pleomorphic adenoma of salivary glands depends almost entirely on the adequacy of primary excision. Recurrence is very high if the tumour is removed by a simple enucleation. Most recurrences will appear in the first 18 months after surgery. Surgery for recurrent tumour often fails. Thus, the proper therapy for pleomorphic adenoma is its total surgical removal, along with a margin of normal salivary tissue. About 5 to 10% of malignant mixed tumour are believed to develop from previously benign mixed tumours. Such tumours have a carcinomatous appearance (ductal type carcinoma) in contrast to malignant mixed tumours that arises de novo and having a biphasic component.
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