Primary embryonal rhabdomyosarcoma of the breast.

To the Editor: Rhabdomyosarcoma is the most common sarcoma of the soft tissues in children and young adults, and comprises around 5% of malignant neoplasia in this age group. (1-3) Its location in the breast is rare and generally represents metastatic disease from a primary site in another part of the body. (2-5) Primary rhabdomyosarcoma of the breast has rarely been reported in the literature and almost always occurs in adolescent females and presents as tumors of the alveolar subtype. (3,4) Primary embryonal subtype is extremely rare and aggressive, and is associated with an unfavorable outcome. (2-4) Considering the few cases of primary embryonal rhabdomyosarcoma of the breast reported in the literature, we would like to add one more case.

A 15-year-old adolescent Brazilian girl was admitted with a large tumor in her right breast that had begun as a small nodule two years previously. Physical examination revealed a tumor of firm consistency that occupied almost the entire right breast and ipsilateral axillary lymphadenopathy (Fig. A). Following biopsy and confirmation of the diagnosis of embryonal rhabdomyosarcoma, tests were carried out to investigate the clinical extent of the disease and the location of a possible primary site of the lesion in another part of the body. A computed tomography scan of the thorax, facial sinus, abdomen and pelvis found no abnormalities. X-ray of the thorax and long bones, bone scintigraphy, pelvic and abdominal ultrasonography were all normal. The patient then underwent a right mastectomy and axillary lymphadenectomy. Gross examination of the specimen showed a lobulated, firm, elastic tumor measuring 14 X 8.5 X 4.2 cm. Histologic examination revealed infiltrative neoplasia comprising small hyperchromatic cells with round, eccentric nuclei and sparse eosinophilic cytoplasm of rhabdoid appearance (Fig. B). Twenty-two lymph nodes were isolated from the axillary content, eight of which were found to contain metastatic cells. Immunohistochemical evaluation revealed positivity for HHF-35, desmin and myogenin, thereby confirming the diagnosis of embryonal rhabdomyosarcoma. The patient and her guardian refused any recommended additional treatment and the patient died as a result of liver and lung metastases, four months after surgery.

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Although rhabdomyosarcoma is the most common neoplasia of the soft tissues in the pediatric age group, its location in the breast is very rare and generally, when it occurs, consists of metastatic disease. (2-5) These rare metastases of rhabdomyosarcoma of the breast are seen principally in adolescent girls. (3) Their site of origin may be the head, neck, genital or urinary tracts, retroperitoneal tract, extremities or trunk. (2-4) Primary rhabdomyosarcoma of the breast is, therefore, very rare. (5)

The embryonal subtype of primary rhabdomyosarcoma of the breast is extremely rare (2-4) and, as far as we know, only 8 cases have been reported in the literature. They are aggressive, rapidly growing tumors; however, from a clinical point of view, delays in diagnosis are frequent, as inferred by the large size of the primary breast tumors and some initial metastases reported in the Intergroup Rhabdomyosarcoma Study series. (4) A complete physical examination and diagnostic imaging of other parts of the body should be carried out to eliminate the possibility of primary neoplasia at other sites that have metastasized to the breast. (2-4) In this case, there was no evidence of a primary tumor in other locations. The treatment of rhabdomyosarcoma, in this unusual site, includes an ample excision and even radical mastectomy followed by chemotherapy using multiple agents. (2) Embryonal rhabdomyosarcomas have a poor prognosis irrespective of therapy, (4,5) as seen in the present case.

Benedito Borges Da Silva, MD, PhD

Pedro Vitor Lopes-Costa, MD

Lina Gomes dos Santos, MD

Cleicilene Gomes Pires, MD

Marina Vilarinho Correa-Lima, MD

Cleriston da Silva Moura, MD

Department of Gynecology

Federal University of Piaui, Teresina

Piaui, Brazil

References

1. Bianchi L, Orlandi A, Iraci S, et al. Solid alveolar rhabdomyosarcoma of the hand in adolescence: a clinical, histologic, immunologic, and ultrastructural study. Pediatr Dermatol 1995;12:343-347.

2. Herrera LJ, Lugo-Vicente H. Primary embryonal rhabdomyosarcoma of the breast in an adolescent female: a case report. J Pediatr Surg 1998;33:1582-1584.

3. Sheen-Chen SM, Eng HL, Ko SF. Metastatic rhabdomyosarcoma to the breast. Anticancer Res 2005;25:527-529.

4. Hays DM, Donaldson SS, Shimada H, et al. Primary and metastatic rhabdomyosarcoma in the breast: neoplasms of adolescent females, a report from the Intergroup Rhabdomyosarcoma Study. Med Pediatr Oncol 1997;29:181-189.

5. Boothroyd A, Carty H. Breast masses in childhood and adolescence. A presentation of 17 cases and a review of the literature. Pediatr Radiol 1994;24:81-84.Letters to the Editor