Primary spindle rhabdomyosarcoma of the breast in an adult female

Recurrent malignant phyllodes tumor of the breast: An extremely rare case of recurrence with only rhabdomyosarcoma components

Rhabdomyosarcoma is a rare disease that typically occurs in children. Rhabdomyosarcoma seldom occurs in the breast, and its diagnosis and treatment have infrequently been reported. The present case is a rare one of a recurrent malignant phyllodes tumor of the breast with only rhabdomyosarcoma components. A 69-year-old woman received a diagnosis of borderline phyllodes tumor of the left breast and underwent partial mastectomy. During follow-up, a left breast mass was found 1 year and 8 months after the previous surgery. Based on examination findings, it was suspected to be recurrent phyllodes tumor, so total left mastectomy was performed in our hospital. After the surgery, immunostaining failed to determine the epithelial component which may be produced by the proliferative part of stromal cells of previous phyllodes tumors. However, we could not exclude the possibility that this was a new tumor. After comparing samples with specimens from the first operation, it was finally determined to be a malignant phyllodes tumor with a rhabdomyosarcoma component. Therefore, chemotherapy was given, and vincristine, actinomycin D, and cyclophosphamide therapy was introduced. At the same time, radiation therapy was planned. Among phyllodes tumors, cases involving rhabdomyosarcoma components are very rare, especially those where the recurrence morphology only shows the same rhabdomyosarcoma components. This was a rare case with unique characteristics and great reference value.

Primary Rhabdomyosarcoma of the Breast: Study of Three Cases at One Institution with a Review of Primary Breast Sarcomas

BACKGROUND

Primary breast sarcoma (PBS) is rare, comprising approximately 1% of breast malignancies. Rhabdomyosarcoma (RMS) accounts for an extremely small proportion of PBSs, often leading to delayed histologic confirmation.

METHODS

Upon reviewing Asan Medical Center's pathology database between 2000 and 2018, 41 PBS cases were retrieved, including three cases of primary RMS of the breast. Their clinicopathological features were analyzed, and the literature related to PBS and primary RMS of the breast was reviewed.

RESULTS

We identified three primary breast RMS cases from our institution database, comprising 7.3% of PBS: one case each of spindle cell/sclerosing RMS (ssRMS), alveolar RMS (aRMS), and embryonal RMS (eRMS). All cases involved adolescents or young adults (14, 16, and 25 years, respectively) who underwent mastectomy or radiotherapy and were confirmed using immunohistochemical testing for myogenin, desmin, and myogenic differentiation. The ssRMS patient experienced recurrence at the operation site 4 months post-surgery despite undergoing concurrent chemoradiotherapy. The aRMS patient had multiple metastases at diagnosis and showed FAX3-FOXO1 fusion transcripts; she died 22 months after the diagnosis. The eRMS patient had enlarged axillary lymph nodes; post-radiotherapy, the lesion recurred as multiple metastases to the bone and lung. She died 18 months post-diagnosis.

CONCLUSIONS

Our experience on RMS cases suggests that spindle cell or small round cell malignancy in breasts of young female should raise suspicion for the possibility of primary or secondary RMS. To our knowledge, this is the second report of primary breast ssRMS and it may help clinicians who encounter this rare disease in the future.

Primary Alveolar Rhabdomyosarcoma of the Breast in an Adult: An Extremely Rare Case

Sarcomas of the breast constitute less than 1% of all malignant breast tumors and primary rhabdomyosarcoma (RMS) is a very rare entity with limited case reports in the literature. RMS is common in children and adolescents and rare in adults. Primary RMS arising from the breast is exceedingly rare in adults. We report a case of a primary RMS of the breast in a 60-year-old woman, who presented in an early stage, mimicking invasive ductal carcinoma clinically and is in complete remission after three years of diagnosis and one year of treatment.