Fine needle aspiration cytology of dermal cylindroma.

In this paper, we have described fine needle aspiration cytology (FNAC) of a rare case of dermal cylindroma. A 40-year-old female presented with a lateral mid-cervical swelling fixed to the skin. FNAC smears showed multiple clusters of small, round to oval cells with hyperchromatic nuclei, inconspicuous nucleoli and scant cytoplasm. In addition, the background showed deposits of basement membrane type material. This was dark magenta colored pinkish globular material. The globules were occasionally surrounded by the basal type of cells. Occasional cells with elongated nuclei were also noted. Cytological diagnosis of skin adnexal tumor possibly cylindroma was offered. Subsequent histopathology of the swelling showed sheets and clusters of cells in a jigsaw puzzle-like fashion. Deposition of abundant basement membrane-like material was noted in between the tumor cells. A diagnosis of cylindorma was offered. FNAC along with the subcutaneous location of the tumor and absence of primary salivary gland tumor may help to diagnose such rare case.

Introduction

Cylindroma is a benign adnexal tumor of the skin with eccrine and apocrine differentiation. It commonly occurs in the scalp, face and extremities.[1] It is also known as turban tumor because of its typical turban like growth in the scalp. Fine-needle aspiration cytology (FNAC) diagnosis of cylindorma has rarely been described in the literature.[2] Herein, we report a rare case of fine needle aspiration findings of a dermal cylindroma diagnosed on FNAC and subsequently confirmed on histopathological examination.

Case Report

A 40-year-old housewife presented to us for evaluation of a right sided mid-cervical swelling. The swelling was painless and was gradually increasing in size for last 8 months. She had no other swelling in other parts of the body and had no constitutional symptoms. Examination revealed a well-defined 2 cm × 2 cm, nontender, firm, nodular swelling of the neck. The overlying skin was fixed to the swelling, but there was no erythema, induration, ulceration or puckering of the overlying skin. The swelling was not fixed to the deeper structures.

Cytology

Aspirate obtained from the swelling was blood mixed and particulate. The smears were cellular and showed multiple clusters and discrete small, round to oval cells with hyperchromatic nuclei, inconspicuous nucleoli and scanty cytoplasm. In addition, the background showed deposits of basement membrane type material. This was dark magenta colored pinkish globular material. The globules were occasionally surrounded by basal type of cells. Occasional cells with elongated nuclei were also noted. A diagnosis of benign adnexal tumor, likely cylindroma, was offered [Figure 1a and b].

Figure 1

(a) Cytology smear shows discrete and tight clusters of small roundcells (MGG, ×240). (b) cytology smear shows pinkish basement membrane like material surrounded by round cells (MGG, ×440) (c) Histology section of cylindroma showing acellular basement membrane like material along with round cells (H and E, ×220)

Histology

The patient underwent excision biopsy. Gross examination showed a well-circumscribed 2 cm diameter grey-white skin covered swelling. Histopathological examination of the swelling revealed a well-circumscribed, highly cellular tumor. The tumor cells were arranged in the form of sheets and clusters in a jigsaw puzzle-like fashion. Deposition of abundant basement membrane-like material was noted in between the tumor cells. The tumor cells were small, round to oval with hyperchromatic nuclei, inconspicuous nucleoli and scant cytoplasm. No nuclear atypia, increased mitotic activity, necrosis or invasion into the surrounding structures was noted [Figure 1c]. Based on these features, a diagnosis of cylindroma was made.

Discussion

Dermal cylindromas are most commonly seen in middle-aged and elderly females with preponderance in the head and neck region, especially over the scalp. Most cases are sporadic and present with solitary lesions. However, when associated with familial inheritance, they tend to be multiple.[3] Clinically, cylindorma presents as single or multiple, dome-shaped, smooth, nodular lesions over scalp, face and in rare instances, over trunk and extremities. Numerous nodular swellings over the scalp may give rise to the characteristic appearance of a “turban tumor.”

In this present case the round pinkish acellular material surrounded by round monomorphic cells and discrete monomorphic round cells suggest features of cylindroma. The present case may be mistaken as adenoid cystic carcinoma of salivary gland. Cytologically it is difficult to distinguish cylindroma from adenoid cystic carcinoma of the salivary gland.[24] Bondeson et al.[2] in their study warned on this aspect and suggested restricted excision before any wide excision surgery. However, we feel that the absence of salivary tumors and swelling fixed in the subcutaneous tissue may indicate the dermal origin of the tumor.

Eccrine spiradenoma may also show ball-like clusters of cells and pinkish globular structure. However, the cytology smear shows myoepithelial cells and lymphocytes. Rosette like structures is also noted in FNAC of eccrine spiradenoma cases.[5]

In the case of chondroid syringoma, the fibrillary chondromyxoid substances are noted, and the cells are embedded in such material. The epithelial cells are arranged in flat sheets. The cells are small round with oval nuclei having fine chromatin. Typical hyaline-like globules are not seen in such cases.[6]

Conclusion

We report here a rare case of cylindroma in neck region. The characteristic cytological features on FNAC along with the subcutaneous location of the tumor and absence of primary salivary gland tumor may help to diagnose such rare case.