Lipomatous pleomorphic adenoma of parotid gland

Lipomatous basal cell adenoma (Basal cell lipoadenoma) - Report of the first two cases

We present, to the best of our knowledge, the first two cases (60 year old female and 71 year old male) of basal cell adenoma with significant adipocytic components and suggest the term "lipomatous basal cell adenoma" for these lesions. Both tumors presented as slow growing nodules in the parotid gland. The two cases represent different points on a histopathological spectrum with one case being extremely well differentiated with distinct spiradenoma-like histological features; distinct bilayering, duct formation with secretory material and very low proliferative activity and the other case displaying more primitive cytological features composed of a predominant uniform, (p63-positive; CK 7-negative) basaloid, abluminal cell type, high proliferative activity and only scattered true ducts composed of (CK7-positive, p63-negative) luminal cells.

Lipomatous pleomorphic adenoma in the hard palate: Report of a rare case with cyto-histo correlation and review

Pleomorphic adenoma is the most common benign tumor of the salivary glands. They are usually composed of epithelial/myoepithelial cells and chondromyxoid stroma. Extensive lipomatous differentiation is very rare. We report a case of lipomatous pleomorphic adenoma (LPA) that presented with a mass in the hard palate of a 32-year-old woman. The fine-needle aspiration cytology material was reported as benign cytology consistent with adenoma with major adipocytic component. Histopathological examination of the excision material displayed that more than 90% of the tumor was adipocytic in texture, containing scant epithelial and myoepithelial cells and chondromyxoid stromal fragments. Preoperative cytodiagnosis of lipomatous pleomorphic adenoma on FNA is based on cytomorphology intimately associated pleomorphic adenomatous and lipomatous tissue elements. LPA should be on the mental list of the (cyto)pathologist in differential diagnosis of lipomatous tumors or non-tumorous lipomatosis or carcinoma invasion in the adipose tissue of the minor salivary gland of the hard palate.

Fat-containing salivary gland tumors: a review

Fat-containing tumors of the salivary glands are uncommon. Their wide histological spectrum varies from pure lipomatous neoplasms similar to their cutaneous and soft tissue counterparts to mixed lipoepithelial lesions specific to the salivary glands. With few exceptions, these uncommon lesions affect mainly the elderly, with a mean age at presentation of ≥ 50 years and show a predilection for males. A few cases occur in childhood; some of them represent congenital lesions. In decreasing order of frequency, ordinary (soft-tissue type) lipoma, oncocytic lipoadenoma, non-oncocytic sialolipoma, and pleomorphic adenoma/myoepithelioma with extensive lipometaplasia are the main variants of fat containing tumors encountered in the salivary glands. While pleomorphic adenoma/myoepithelioma with lipometaplasia behave in the same way as their non-fat-containing counterparts, other lipomatous salivary gland tumors listed above are cured with simple excision and do not carry a risk of recurrence. Other lipoma variants (spindle cell lipoma, osteolipoma, fibrolipoma, angiolipoma, pleomorphic lipoma, lipoblastoma and hibernoma) are exceptionally rare in the salivary gland. Atypical lipomatous tumors/liposarcoma have been only rarely reported in the salivary gland and they behave in a similar fashion to their soft-tissue counterparts. Diffuse lipomatosis and lobular fatty atrophy are the two tumor-like lesions that might closely mimic sialolipoma, particularly in limited biopsy material without knowledge of the gross findings. This review summarizes the clinicopathological features of the main types of salivary fat-containing lesions and discusses their differential diagnoses.

Lipomatous salivary gland tumors: a series of 31 cases spanning their morphologic spectrum with emphasis on sialolipoma and oncocytic lipoadenoma

Lipomatous neoplasms of the salivary glands are rare. Their wide histologic spectrum has not been sufficiently studied. We collected 31 fat-containing salivary gland lesions excluding pleomorphic adenoma and myoepithelioma with lipometaplasia. There were 19 male and 12 female patients aged 7 to 89 years (mean, 53 y). Tumors originated in the parotid (n=29) and the submandibular (n=2) gland. On the basis of the proportion and distribution of adipose tissue and the epithelial type, tumors could be categorized into 3 main groups: ordinary lipoma (n=20) identical to soft tissue lipoma but located within the salivary gland, oncocytic lipoadenoma (n=6) composed predominantly of oncocytes with variable fatty component, nononcocytic sialolipoma (n=4) composed of lobular fatty tissue (≥70%) with evenly distributed normal salivary tissue recapitulating the composition of normal salivary glands and microcystic lipoadenoma (n=1) composed of cystic ducts admixed with adipose tissue. The mean tumor size was 3.3, 3.8, and 2.9 cm for lipoma, oncocytic lipoadenoma, and nononcocytic sialolipoma, respectively. Associated diseases included Madelung disease with bilateral atypical lipomatous tumors of the neck and bilateral parotid lipoma (1), oncocytic lipoadenoma after irradiation for sinonasal adenocarcinoma (1), and periparotideal lipoma excised years before oncocytic lipoadenoma (1) and nononcocytic sialolipoma (1). No recurrence was recorded at a mean follow-up of 72 months (range, 6 to 184 mo). Sebaceous islands were seen in 5/6 oncocytic lipoadenomas and in 2/4 sialolipomas. Periductal inflammation/fibrosis was common in sialolipoma and oncocytic lipoadenoma. This study demonstrates the wide morphologic spectrum of fatty salivary gland lesions. Oncocytic lipoadenoma is an epithelial-predominant tumor that is distinct from the fat-dominated nononcocytic sialolipoma, but the 2 types seem to merge in some cases.

A case of lipomatous pleomorphic adenoma in the parotid gland: a case report

Introduction

Pleomorphic adenoma is the most common benign neoplasm of the salivary glands. Extensive lipomatous involvement of the tumor is, however, a very rare finding.

Case report

Herein, a rare case of lipomatous pleomorphic adenoma arising in the parotid gland of a 14-year-old Japanese woman is presented.

Conclusion

This is the sixth case of lipomatous pleomorphic adenoma in the English literature. Recognition of this rare subtype of pleomorphic adenoma is important for clinical diagnosis and management. On CT scan, it may not be detected possibly due to the extensive fatty component.

Lipomatous pleomorphic adenoma of the ceruminous gland

A case of lipomatous pleomorphic adenoma in the ceruminous gland is reported. A 69-year-old Japanese woman presented with a mass in the posterior wall of the cartilaginous external auditory canal. Light microscopic examination revealed a well-circumscribed tumor composed of tubular structures with apocrine secretion and ceroid deposition, extensive mature adipocytes, and spindle-shaped myoepithelial cells in the myxoid and fibrous stroma. This case demonstrates the peculiar location of a lipomatous pleomorphic adenoma in the external auditory canal.