Cylindroma of the breast: a rare case report.

Cylindroma is a benign adnexal tumor, which occurs as solitary dermal nodules on the scalp and forehead. Cylindroma of the breast is a rare lesion. Fine-needle aspiration is often the first line of investigation. In this communication, we illustrate the cytomorphological feature of cylindroma in a 61-year-old female patient who presented with a breast lump. Fine-needle aspiration cytology in this case reveals the islands of tumor cells formed a "jig-saw" pattern, along with the bland, basaloid cells associated with globular, extracellular material. These features are typical of cylindroma, but differential diagnosis of adenoidcystic carcinoma should always be kept in mind as the management of both tumors are different.

INTRODUCTION

Cylindromas are benign skin appendage tumors. They most commonly occur on the head and neck as solitary or multiple tumors. Cylindroma of the breast is an extremely rare entity. To the best of our knowledge only eleven cases have been published so far.[1234] Cylindroma of the breast is morphological and immunophenotypically identical to benign dermal cylindroma. We discuss here the salient cytomorphological feature of breast cylindroma so that they can be correctly diagnosed and managed.

CASE REPORT

The present case report is about a 61-year-old woman who presented with freely mobile, firm, non-tender right breast mass of 2 cm diameter in upper inner quadrant since 4 years. There were no skin or nipple changes and no axillary lymphadenopathy. The patient had no significant family history or skin nodules. Mammography showed a well-circumscribed mass in the 1 o‘clock position of the right breast [Figure 1]. According to The Breast Imaging Reporting and Data System the score was 3 which mean that mammogram was probably normal, but a repeat was suggested. Ultrasonography showed well-defined heterogeneous mass noted in the right breast. Subsequently, fine-needle aspiration cytology was done using 22-G needle. Papanicolaou staining was done. Smears show numerous basaloid cells with scanty cytoplasm and round nuclei seen lying in jigsaw puzzle pattern [Figure 2]. Diagnosis of “probably benign” (C2) was made and biopsy was advised. The nodule was excised. Histological sections stained by hematoxylin and eosin revealed nests of basaloid cells arranged in a complex jigsaw puzzle like pattern. Many nests are surrounded by dense eosinophilic basement membrane material and thus confirmed the diagnosis of cylindroma [Figure 3]. The patient was followed for 12 months, which remained uneventful.

Figure 1

Mammogram image showing a well-circumscribed mass in the 1 o’clock position of the right breast (mediolateral oblique view)

Figure 2

Smears show numerous basaloid cells with scanty cytoplasm and round nuclei seen lying in jigsaw puzzle pattern (arrow) (Pap stain, ×200). Insat: Smears show numerous basaloid cells with scanty cytoplasm and round nuclei (Pap stain, ×400)

Figure 3

Sections revealed nests of basaloid cells arranged in a complex jigsaw puzzle like pattern. Many nests are surrounded by dense eosinophilic basement membrane material (H and E, ×200)

DISCUSSION

Cylindromas are uncommon dysplasias of the skin appendages. The word cylindroma was first used by billroth in 1959 in the description of adenoid cystic carcinoma (ADCC). It is derived from the histopathological appearance of tumor where the nests of cells surrounded by hyaline, resemble a cylinder in cross section. Cylindromas are relatively benign skin adnexal tumors occurring most commonly on the head and neck as a solitary nodule. Multiple cylindromas may grow together in a “hat-like” configuration, the so-called “turban tumor.” Familial cylindromatosis or Brooke-Spiegler syndrome is a rare familial condition with autosomal dominant mode of inheritance and tends to form numerous adnexal tumors, in particular trichoepithelioma, cylindroma and occasionally spiradenoma. The lesions are widely distributed not only on the head and neck, but also the trunk and extremities. It is associated with mutations in the CYLD 1 gene.[5] Cylindroma are conventionally classified as a neoplasm of apocrine differentiation, but the ultrastructural and immunohistochemical evidence has also been presented in favor of an eccrine origin of cylindroma.[67] On the other hand, the fact that cylindromas exclusively arise in hair follicle-bearing regions of the integument, but not in eccrine rich palmoplantar skin, which is devoid of pilosebaceous units and apocrine glands, already indicate against an eccrine origin.

According to Massoumi et al.[8] cylindroma epithelium likely originates from epithelial hair follicle, whose exact differentiation pathway (follicular vs. apocrine vs. sebaceous and may be even eccrine) may be dictated by the nature of the epithelial–mesenchymal signaling in a given patient and skin location as in every normal hair follicle.

Despite the deployment of a wide range of immunohistological, histochemical markers and ultrastructural studies, the histogenesis of cylindromas has remained a subject of continuous debate.

Cylindroma of the breast is a rare entity first described in 2001 by Gokaslan et al.[1] Extensive literature search showed only eleven reported cases of breast cylindromas.[1234] Breast is considered as a modified sweat gland. Hence it can give rise to sweat gland type neoplasm; cylindroma of the breast is one such type of neoplasm.

Fine-needle aspiration is often the first line of investigation of breast lesions. The Cytomorphology of cylindroma of breast is indistinguishable from dermal cylindroma. Cytological smears are usually richly cellular comprising of two types of cells arranged in diffuse fashion or poorly formed acinar pattern. Small cells show scant cytoplasm and darkly stained round to oval nuclei and the other large cells with relatively abundant cytoplasm and round to oval vesicular pale staining nuclei. The cells may be associated with hyaline globules.

Histologically, the lesions are identical morphologically to dermal cylindromas. Cylindromas consist of nests and trabeculae of cells that mold in a “jigsaw” or “mosaic” appearance. The nests are composed of peripheral basaloid cells with bland darkly stained nuclei and central larger cells with oval vesicular nuclei. The nests also show few duct-like lumina with or without secretions. The nests are separated by thick basement membrane material, which shows periodic acid Schiff positivity with diastase resistance and immunoreactivity to collagen type-IV. Hyaline globules are present focally within the cell nests. Immunohistochemically, basaloid cells show diffuse positivity for p63 whereas larger central cells show CK7-positivity.[4]

Cylindroma of the breast has to be differentiated from solid type of ADCC both on cytological and histological examinations. Morphologically both tumors have a nodular and trabecular appearance, they also share basaloid and central paler cells. Both tumors also show hyaline globules, basement membrane material and duct like lumina. However, ADCC shows moderate to marked nuclear atypia and brisk mitotic activity which are absent in cylindroma.[9] ADCC may be associated with mucin production, a finding absent in cylindroma.

ADCC has an excellent prognosis, but there have been reported cases with local recurrence and distant metastases.[10] Breast cylindroma always runs a completely benign course when treated with wide local excision. Whereas, mastectomy or excisional biopsy with adjuvant radiotherapy has been recommended as treatment of solid-variant of mammary ADCC.[9]

In this case, the mass was small and well -circumscribed for 4 years and also there was benign impression on cytology and imaging. This made the surgeon to proceed with excision of the mass rather than going for mastectomy.

Primary Breast cylindroma are extremely rare benign tumor. These should be distinguished from ADCC as the correct diagnosis may obviate the need for unnecessary mastectomy.