Lymphoid and epithelial lesions may arise from intraparotid LNs, which originate from the inclusions of salivary ducts and acini.2–7
The frequency of these lesions increases dramatically when cystadenoma lymphomatosum cases, which are thought to arise from intranodal ductal inclusions, are considered.8
Multiple lumps at this region are frequently related to lesions originating from LNs, and the leading lesion is again cystadenoma lymphomatosum.9
In our present case, histopathological examination revealed extensive SM of the intranodal inclusions, with a preserved lobular architecture involving five intraparotid LNs. Among the previous reports we noticed cases comparable to this one. Goldman and Klein2
described PS of an intraparotid lymph node. Ryan et al
described two patients with AIDS who presented with lumps at the parotid region, with lymphadenitis and SM of the salivary gland ductal inclusions.3
As in our present case, those cases did not fulfill the established criteria for the diagnosis of necrotising sialometaplasia1
described by Abrams et al
because we could not consistently demonstrate infarction. Anneroth and Hansen10
suggested five stages in the course of necrotising sialometaplasia, namely: infarction, sequestration, ulceration, reparation, and healing. The lesions in our patient might represent the reparation and healing stages of necrotising sialometaplasia, but without evidence of necrosis the case falls into the category of proliferative SM.
Take home messages
- We report a unique case of proliferative sialometaplasia of multiple intraparotid lymph nodes occurring in a 55 year old woman, presenting with multiple parotid lumps
- This interesting case points to the importance of intraparotid lymph nodes as sites for multiple lesions of the parotid region
“We feel that this unique case is important because, to the best of our knowledge, this is the first case of proliferative sialometaplasia involving multiple intraparotid lymph nodes”
The differential diagnosis of proliferative SM also includes metastatic squamous cell carcinoma and mucoepidermoid carcinoma.2,10,11
In our present case, no cellular atypia or mitotic activity was encountered, thus excluding carcinoma. The coexpression of cytokeratin, S-100, and actin was consistent with a lesion related to myoepithelial cells. The lack of chondromyxoid stroma and the presence of multiple intranodal lesions aided in the exclusion of squamous metaplasia prominent pleomorphic adenoma.2
The patient’s clinical features were inconsistent with the established criteria12
of Sjögren’s syndrome and the involvement of intraparotid lymph nodes has not been described for this disease.
We feel that this unique case is important because, to the best of our knowledge, this is the first case of PS involving multiple intraparotid LNs. PS should be included in the differential diagnosis of multiple lumps of the parotid region.