| Abstract|| |
Chondroid syringoma (CS) also known as mixed tumor of the skin, is a rare benign adnexal tumor accounting for < 0.098%. Epithelial cells arranged in cords and tubules set in myxoid or chondroid stroma. Differentiation such as osteoid, sebaceous or mature adipocytes can be seen rarely. Hyaline cell rich is a rare variant of CS composed of cells with eosinophilic hyaline cytoplasm and plasmacytoid features. CS can have benign, atypical and malignant variants. The term atypical mixed tumor is recommended for those tumors which have histological features of malignancy such as infiltrative margin, satellite tumor nodules and tumor necrosis but without proven metastasis. Very few case reports of hyaline cellrich benign CS have been reported in the past, but to the best of our knowledge, possibly it is the first case of atypical hyaline cellrich CS of the little finger in a 65 year-old female showing divergent differentiation.
Keywords: Chondroid syringoma, cutaneous mixed tumor, histopathology, hyaline cells
|How to cite this article:|
Masamatti SS, Vijaya C, Narasimha A. A rare case of hyaline cell-rich atypical chondroid syringoma with divergent differentiation. Indian J Pathol Microbiol 2018;61:428-30
|How to cite this URL:|
Masamatti SS, Vijaya C, Narasimha A. A rare case of hyaline cell-rich atypical chondroid syringoma with divergent differentiation. Indian J Pathol Microbiol [serial online] 2018 [cited 2020 Aug 15];61:428-30. Available from: http://www.ijpmonline.org/text.asp?2018/61/3/428/236591
| Introduction|| |
Chondroid syringoma (CS) is a rare benign tumor of skin with the incidence <0.098% of all primary cutaneous tumors, which was first described by Billroth in 1859 for salivary gland tumors. Virchow and Minssen referred to these tumors as “mixed tumors” as they consisted of both epithelial and mesenchymal elements. Mixed tumors can occur in skin, salivary glands, breast, kidney, lungs etc., It usually presents as a slow-growing, painless, subcutaneous or intradermal nodule. Cutaneous adnexal tumors constitute a wide spectrum because they can differentiate along one or more of the adnexal lineages. There are many cases of benign CS and few malignant CS reported worldwide, but very few cases of atypical CS have been reported till date. We report a rare case of hyaline cell-rich atypical CS with divergent differentiation of left little finger in a 65 year-old female, which is again an unusual site for this tumor.
| Case Report|| |
A 65 year-old female presented with a slowgrowing, painless swelling of the tip of left little finger for 6 months. It was a well circumscribed mass measuring around 3 cm in diameter. X-ray of the hand did not show the involvement of the underlying bone [Figure 1]a. Workup for metastasis such as chest Xray and whole body computed tomography scan was negative. A diagnosis of lipoma was made clinically and fine needle aspiration cytology was advised but revealed only hemorrhage. Hence, excision biopsy was performed and specimen was sent for histopathological examination.
|Figure 1: (a) Clinical photograph of swelling along with radiographic picture (b) gross and cut surface of the mass (c) microphotograph showing tumor cells arranged in sheets along with satellite nodules (H and E, ×100 ) (d) cells showing mild to moderate pleomorphism and occasional mitosis (H and E, × 400)|
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The tumor was globular, well circumscribed, firm, graytan mass measuring 3 cm in diameter. Cut surface showed glistening homogeneous graywhite surface [Figure 1]b.
Microscopic examination revealed a well circumscribed mass composed of sheets and nests of epithelial cells having plasmacytoid appearance with eccentrically placed nuclei and having a moderate amount of deeply eosinophilic, “hyaline-like” cytoplasm embedded in a chondromyxoid-rich stroma. Many of the cells showed pleomorphic vesicular nuclei with prominent nucleoli and mitosis. Small satellite nodules were noted outside the main tumor [Figure 1]c. There was no evidence of necrosis. The stroma showed keratinous differentiation in the form of keratinous cysts, lipomatous, osteoid, sebaceous, myxoid and chondroid differentiation along with foci of calcification. At few places, the tumor showed infiltrative margins and mild to moderate pleomorphism [Figure 1]d. Stroma showed intense positivity for alcian blue, and hyaline cells were PAS positive [Figure 2]a and [Figure 2]b. Immunohistochemistry showed that these tumor cells were positive for S-100 and CAM 5.2 [Figure 2]c and [Figure 2]d. Based on histopathological features and immunohistochemistry, a diagnosis of hyaline cell rich atypical CS with divergent differentiation was given.
|Figure 2: Microphotograph demonstrating stroma (a) intense positivity with alcian blue stain (alcian blue stain, ×100) (b) hyaline cells showing intense PAS positivity (PAS, ×400) (c) cytoplasmic S-100 positivity in plasmacytoid epithelial cells (S-100, ×400) (d) tumor cells showing CAM 5.2 expression (CAM 5.2, ×400)|
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There was no evidence of metastasis or recurrence after 6 months of surgery.
| Discussion|| |
CS is usually seen in elderly males located in the head and neck region, usually < 3 cm, but exceptionally large benign CS has been reported in the past. Other rare sites include axilla, abdomen, trunk, genitalia, eyelid, orbit and extremities., Apart from benign tumors, atypical and malignant forms of CS have also been reported. Unlike benign tumors, malignant forms are seen in young women, rapidly growing tumors > 3 cm, with or without erosion or ulceration of the overlying skin. Clinically this tumor can be mistaken for sebaceous cyst, dermoid, neurofibroma, pilomatricoma, seborrheic keratosis, solitary trichoepithelioma, lipoma, hemangioma, dermatofibroma, myxoid liposarcoma, and extraskeletal chondrosarcoma when located over distal hallux.,
Histopathological features of malignancy include necrosis, atypical mitosis, nuclear pleomorphism, satellite nodules, infiltrative margins and vascular invasion. The term “atypical mixed tumor” is recommended for those tumors which have histological features of malignancy but without proven metastases. Our case had all histological features of malignancy but there was no evidence of metastasis hence the diagnosis of atypical mixed tumor was given.
Hirsh and Helwig proposed the following histological criteria for the diagnosis of CS: 1) nests of cuboidal or polygonal cells 2) intercommunicating tubuloalveolar structures lined by two or more rows of cuboidal cells 3) ductal structures lined by two layers of cuboidal cells 4) occasional keratinous cyst and 5) a matrix of varying composition. Headington recognized two types of CS such as apocrine and eccrine. Histologically, follicular and sebaceous differentiation along with the presence of Merkel cells can be seen and was first described by Salama et al. However, lipomatous, clear cell changes, osteoid formation and calcification can also occur. All these differentiation were noted in our case too. Lomax-Smith and Azzopardi described the characteristic “hyaline or plasmacytoid” cell and thought to be of myoepithelial origin. Such CS is termed as “hyaline cellrich CS or hyaline cellrich apocrine mixed tumor.” It is seen even in atypical and malignant forms of CS and its presence doesnot carry any significance. It is important to identify this entity because it can be confused with malignant melanoma or chondrosarcoma (extraskeletal). In our case also hyaline cells predominated. This diagnostic entity is very rare, and about 9-10 cases of hyaline cellrich benign CS have been reported worldwide, but to the best of our knowledge, this is the first case of hyaline cellrich atypical CS seen in 65 year-old female showing divergent differentiation and occurring at hallux of left little finger, which is again a rare presentation.
Immunohistochemistry of inner layer in CS shows expression of cytokeratin, epithelial membrane antigen and carcinoembryonic antigen which is characteristic of epithelial lineage whereas outer layer cells expressed vimentin, S-100, neuronspecific enolase and glial fibrillary acidic protein in few cases, which is characteristic of both epithelial and mesenchymal differentiation. Mills suggested that mixed tumors are monoclonal neoplasms which may differentiate toward epithelium or mesenchyme and also account for the histologic variability of mixed tumors of skin. In tumors involving small bones, as seen in our case, chondrosarcoma may enter into one of the important differential diagnoses. Malignant CS shows immunoreactivity for CAM 5.2 and S-100, whereas in chondrosarcoma tumor cells show only S-100 positivity.
| Conclusion|| |
We present this case because of its rarity and unusual presentation. Complete excision of CS is necessary because of its malignant potential and recurrence. Hence regular longterm followup is recommended for all CSs. Pathologists should be aware of hyaline cellrich variant of CS to avoid misdiagnosis.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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Smita S Masamatti
DQ 14, Sapthagiri Staff Quarters, Sapthagiri Hospital, Chikkasandra, Hesarghatta Main Road, Bengaluru - 560 090, Karnataka
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2]