Myxoma of the breast: Report of a case with unique histological and immunohistochemical appearances

Abstract

A case of myxoma of the breast is reported. The patient, a 19 year old Japanese woman, showed a lump in the left breast which had enlarged gradually over 3 years. A tumor measuring 5 × 5 × 4.5 cm was located mainly in the mammary parenchyma, but partially involved the overlying subcutaneous tissue. Histologically the tumor was multinodular and each nodule consisted of an abundant myxoid substance with a few spindle or stellate mesenchymal cells. The presence of hyaluronic acid was observed in the myxoid area, and a few constituent cells showed Immunoreactivitiesfor S‐100 protein and α1‐antichymotrypsin. Electron microscopic studies revealed that some constituent cells looked like undifferentiated mesenchymal cells, while others showed a differentiation similar to fibroblast or histiocyte. These findings suggest that the constituent cells might derive from totlpotential primitive mesenchymal cells.

Breast Myxoma: Radiologic and Histopathologic Features

“…Our patient had no sign of Carney's complex. Similar to our case, there are only two breast myxoma cases without Carney complex in the literature (7,8). Although the myxoma was a benign tumor, local recurrence and progression to malignant transformation had been reported (3).…”

Clinico-pathological features of breast myxoma: report of a case with histogenetic considerations

“…Practically, however, the lesions reported in the breast with diffuse myxoid stromal changes are: superficial angiomyxoma [9], nodular mucinosis (first reported as nerve sheath myxoma) [16,17], nodular fasciitis (myxoid variant) [18], neurofibroma (myxoid variant) [19,20], myofibrolastoma (myxoid variant) [21,22], myxofibrosarcoma [23], myxoid liposarcoma [24], and mucocele-like tumors [15]. A list of these lesions, including their main clinico-pathological features, is provided in Table 1.…”

“…Although a computerized literature search has revealed five cases of myxoma of the breast [4,5,[8][9][10], in our opinion, only three well-documented cases are available [4,5,8]. In fact, one case reported with the term "myxoma of the breast" could well represent a superficial angiomyxoma, due to the close relationship with subcutis and its multinodular appearance both at gross and microscopic examination [9]. Another case of breast myxoma involved the subcutaneous tissue of a 37-year-old woman who experienced multiple local recurrences referred as "myxosarcoma" and "myxoid liposarcoma" [10].…”

“…Among benign myxoid lesions, superficial angiomyxoma is a dermal/subcutis lesion [1] which can extend into the underlying breast parenchyma [9]. Unlike myxoma, it has a typical multilobular appearance both at gross and microscopic examination due to the presence of fibrous septa [1].…”

Case reports of two unusual breast lumps

“…Tumour was multinodular measuring 5 x 4.5 cm and was diagnosed on histopathology. 6 Mammary myxoma usually presents as subareolar swelling of more than one year duration with size of more than 5 cm. 5,6 Diagnosis is made on the basis of mucinous matrix with a network of fine collagen and fibroblasts.…”