Leiomyosarcoma is not rare among soft tissue tumors. It can exist in any part of the body. However, its most common primary sites are the uterus, retroperitoneum, subcutaneous tissues and gastrointestinal tract (Cohen et al.,
2007; Insabato et al.,
2004; Szekely et al.,
2001). Leiomyosarcomas of the breast are extremely rare, either primary (Abd El All,
2006; Adem et al.,
2004; Gupta,
2007; Hussien et al.,
2001; Jayaram et al.,
2005; Munitiz et al.,
2004; Vu et al.,
2006) or metastatic from other sites (Lin et al.,
2003; Taillibert et al.,
2000). The smooth muscle component might be originated from the blood vessels and sarcomatous change is usually from leiomyoma or other spindle cell tumors (Szekely et al.,
2001). Our presented case should be regarded as primary leiomyosarcoma of the breast since there was no other primary focus being found after a series of surveys including PET scan.
The nipple-areola complex is a circular area of skin that exhibits increased pigmentation and contains numerous sensory nerve endings. The tip of the nipple contains 15 to 20 orifices of lactiferous ducts which are surrounded by a stroma rich in circular and longitudinal smooth muscle bundles, collagen and elastic fibers. The periphery of the nipple-areola complex also contains pilosebaceous units and hair. Therefore, the initial pathologic differential diagnoses should include tumors of both mammary and cutaneous origins. The differential diagnoses and their histological and immunohistochemical features are listed in Table .
| Table 1The initial differential diagnoses and their histological and immunohistochemical features |
The strong and diffuse cytoplasmic expression of α-smooth muscle actin in this case, in additional to the typical cellular morphology, indicates smooth muscle origin of this tumor. According to the previously published cases of mammary, cutaneous and nipple-areola tumors, Ragsdale (
1997)’s minimal criteria for cutaneous leiomyosarcomas, and the WHO classification of breast tumors (Tavassoli and Devilee,
2003), the presence of mitosis, nuclear atypia of various degree depending on differentiation, and hypercellularity are the most important criteria to designate a smooth muscle tumor as sarcoma. Tumor necrosis is not required for the diagnosis of malignancy.
Primary leiomyosarcoma of nipple-areola complex is rare. Table illustrates the cases reported in English literature (Lonsdale and Widdison,
1992; Markaki et al.,
2003; Uğraş et al.,
1997). Histologically, the nipple-areola complex is cutaneous tissue composed of epidermis and dermis. However, in contrast to skin of other sites, it also contains lactiferous ducts that connect to the mammary parenchyma. Table summarizes the clinical features, the treatment and outcome of primary leiomyosarcoma at the nipple-areola complex, the skin of other sites and the mammary parenchyma that reported in literature (Choy et al.,
2006; Holst et al.,
2002; Lonsdale and Widdison,
1992; Markaki et al.,
2003; Uğraş et al.,
1997). Tumors of these various sites had similar cytological and architectural characteristics. However, for primary cutaneous leiomyosarcoma, treatment recommendations include a wide local excision with a 3- to 5-cm margin, including subcutaneous tissue and fascia; while mastectomy, including simple and modified radical mastectomy, is the most common treatment for breast leiomyosarcoma. Due to few cases of primary leiomyosarcoma of nipple-areola complex reported in literature so far, there is no general agreement on whether to treat them as cutaneous or mammary tumors, and the need of adjuvant radio-chemotherapy. An analysis of more cases with a longer follow-up duration is necessary to develop an optimum mode of treatment for leiomyosarcomas at this specific site.
| Table 2Review of cases of primary leiomyosarcomas of the nipple-areola region |
| Table 3Summary of the clinical features of primary leiomyosarcoma of various sites reported in literature |