| Abstract|| |
Spindle cell lipoma (SCL), also called as pleomorphic adenoma, is a rare variant of lipoma histopathologically characterized by an admixture of mature fat cells with spindle cells and occasionally mast cells with myxoid connective tissue stroma and thick bends of birefringent collagen. Although buccal mucosa is the most common location for oral lipomas, for SCL, it is an exceedingly rare location. We report a case of an asymptomatic swelling of buccal mucosa that simulated the features of neurofibroma on histopathological examination, and the final diagnosis of SCL was made on the basis of immunohistochemical features. This is the first documentation of oral SCL using SOX10 to achieve the final diagnosis.
Keywords: CD34, connective tissue tumor, neurofibroma, soft-tissue tumor, SOX10, spindle cell lipoma
|How to cite this article:|
Bajpai M, Pardhe N, Kumar M. Immunohistochemical differentiation between spindle cell lipoma and neurofibroma of oral cavity using CD34 and SOX10. Indian J Pathol Microbiol 2018;61:561-3
|How to cite this URL:|
Bajpai M, Pardhe N, Kumar M. Immunohistochemical differentiation between spindle cell lipoma and neurofibroma of oral cavity using CD34 and SOX10. Indian J Pathol Microbiol [serial online] 2018 [cited 2019 Jan 24];61:561-3. Available from: http://www.ijpmonline.org/text.asp?2018/61/4/561/242984
| Introduction|| |
Lipoma is a benign tumor of connective tissue origin. Many histological variants of lipoma are known and described based on the type of tissue present and predominant in the lesion: fibrolipoma, angiolipoma, myolipoma, myxolipoma, spindle cell lipoma (SCL), osteolipoma, and chondrolipoma. Other less common variants include hibernoma, angiomyxolipoma, and sialolipoma. SCL was first described by Enzinger and Harvey in 1975 as a distinct histopathological entity of conventional lipoma which is composed of spindle-shaped cells with mature adipose tissue in a fibrocellular stroma made up of bundles of ropey collagen fibers. Histopathological differential diagnoses of SCL include solitary fibrous tumor (SFT), neurofibroma, schwannoma, and leiomyoma. An exhaustive literature review revealed 11 cases of intraoral SCL reported in buccal mucosa., This case is being the 12th presentation of SCL of buccal mucosa. This case is a unique presentation of SCL which showed a very close histopathological similarity to neurofibroma and was confirmed by immunohistochemistry.
| Case Report|| |
A 44-year-old male presented to a dental clinic for the evaluation of a painless soft-tissue growth on his left cheek for 1 year. The family and medical history of the patient was noncontributory. Intraoral examination revealed an oval-shaped soft-tissue growth of the left buccal mucosa measuring about 3 cm × 1 cm. The color of the growth was found to be similar to the adjacent mucosa without any sign of ulceration and discharge [Figure 1]a. No sharp-edged cusps were found that could have irritated the mucosa. On palpation, it was soft to firm in consistency and freely movable, preliminarily diagnosis as fibroma was given. The lesion was surgically incised under local anesthesia, and soft-tissue section was sent to the department of oral and maxillofacial pathology for microscopic evaluation. The follow-up period of 6 months was uneventful with satisfactory healing. The written consent of the patient was obtained for the publication purpose.
|Figure 1: (a) Clinical picture of the soft-tissue growth of the left buccal mucosa. 1(b) Admixture of spindle cells and mature adipose tissue (H and E, ×10). (c) Mature adipocytes in a fibrocellular stroma (H and E, ×20). (d) Spindle-shaped cells with wavy nucleus in a myxoid tissue stroma (H and E, ×20)|
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The microscopic examination of hematoxylin- and eosin-stained soft-tissue section revealed a well-circumscribed mass composed of mature adipocytes and abundant spindle-shaped cells [Figure 1]b. The spindle-shaped cells were uniform with wavy elongated nuclei and elongated cytoplasmic processes. The connective tissue stroma was fibrocellular made up of bundles of hyalinized collagen fibers and few dilated blood vessels lined by endothelial cells. The stroma at places showed areas of myxoid degeneration [Figure 1]c and [Figure 1]d. The overlying epithelium was normal stratified squamous epithelium. Based on histopathology, a diagnosis of SCL with the differential diagnosis of neurofibroma was given. Considering the fact that spindle cells seen in the present lesion, shared a close resemblance to the spindle-shaped cells described in neurofibroma. Immunohistochemically, the spindle-shaped cells showed a strong positive expression for CD34 [Figure 2]a and negative expression for SOX10 [Figure 2]b.
|Figure 2: (a) Diffuse positive expression of CD34 for spindle-shaped cells (×20). (b) Negative expression of spindle cells for SOX10 (×20)|
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The final diagnosis of SCL was given based on the correlation of histopathological and immunohistochemical features.
| Discussion|| |
SCL is a rare variant of lipoma.,, Oral SCL is a rare neoplasm with very few reported cases found in the PubMed database. In oral cavity, the most common site is tongue followed by buccal mucosa, palate, and floor of the mouth. One case of central SCL of the maxilla has also been reported. Clinically, the lesions of SCL are usually painless unless secondarily infected. SCL is more commonly reported in males as compared to females with the ratio of 10:1. The mean age of SCL is 55; however, the present case was contrary and reported in a 44-year-old patient.
Histopathologically, they show an admixture of spindle-shaped cells and mature adipose tissue in a variable connective tissue stroma from fibrocellular to myxoid. SCL with floret-like multinucleated giant cells is classified as pleomorphic lipoma.
Histopathological differential diagnoses of SCL include SFT, neurofibroma, and myxoid liposarcoma.,,, Although the diagnosis of SCL is histopathological, at times, it demands an immunohistochemical examination as in the present case.
SCL can be differentiated from myxoid liposarcoma on the basis of histopathological features which include that SCL is located superficially in most of the cases while myxoid liposarcoma is a deep-seated tumor and the other features include that SCL is usually well circumscribed and devoid of pleomorphic adipocytes and lipoblasts. The vascular component of myxoid liposarcoma is more pronounced in comparison to SCL. SFT is relatively rare in oral cavity as compare to SCL; histopathologically, the amount of adipose tissue is lesser in SFT, and vascularization is more pronounced with a staghorn pattern in most of the cases. The spindle-shaped cells in SCL do not demonstrate wavy nuclei; however, the present case was contrary to this finding. Hence, in the present case, the diagnosis was based on immunohistochemistry. SCL occasionally expresses S100 proteins which can cause problems in the differential diagnosis with neural and melanocytic neoplasms and emphasizes the plasticity of the spindle cells in SCL. In the present case, antibodies to CD34 and SOX10 were used. On the one hand, the CD34 positivity was found to be in accordance to the diagnosis of SCL, and on the other hand, SOX10, a neural crest transcription factor, which is responsible for the maturation and specification of Schwann cells and melanocytes, was found to be negative for the spindle-shaped cells. Various studies have shown a strong, diffuse, and positive expression of SOX10 in neurofibromas. Based on negative expression of SOX10, in the present case, the diagnostic possibility of neurofibroma was ruled out. The choice of treatment for oral SCL is surgical excision, and none of the case showed recurrence.,,
It can be concluded that immunohistochemistry is a useful mode for the diagnosis of SCL, especially when the histopathological features are overlapped. This is the first report of oral SCL using SOX10 for differentiation. We believe that SOX10 is a potential marker for oral SCL to make a distinction from the neoplasms of neural origin.
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Conflicts of interest
There are no conflicts of interest.
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Department of Oral and Maxillofacial Pathology, NIMS Dental College, Jaipur, Rajasthan
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2]