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Subspecialties Histology, Oncology

Case of the Month

A 63-year-old woman presented with a left breast palpable lump at 3 o'clock for six months and a family history of breast cancer. Ultrasound examination showed a 0.7 x 0.4 x 0.8 cm cystic and solid superficial mass, corresponding to the palpable mass.

Credit: University of Pennsylvania

Credit: University of Pennsylvania

Credit: University of Pennsylvania

Credit: University of Pennsylvania

Credit: University of Pennsylvania

What is the diagnosis?

A. Nodular fasciitis
B. Dermatofibrosarcoma protuberans
C. ALK-positive histiocytosis
D. Inflammatory myofibroblastic tumor
E. Fibromatosis-like metaplastic carcinoma

Submitted by Mohan Narasimhamurthy and Kumarasen Cooper from the Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania.

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Answer to March’s Case of the Month 

B. Proximal type of epithelioid sarcoma

In 1961, Laskowski was the first to describe epithelioid sarcoma, which he called “aponeurotic sarcoma”. This research was published in Polish (1). Subsequently, epithelioid sarcoma was described by Enzinger in 1970, who also gave it the present name (2). The proximal-type variant, first described in 1997, is an aggressive form of sarcoma with a great ability to metastasize and high capacity of recurrence, even after surgery with radical surgical margins and propensity for early metastasis (3, 4, 5).

Proximal-type epithelioid sarcoma occurs in 94% cases in the chest wall, inguinal region, thigh and perineum. Its size at presentation varies from 0.5 to 19 cm (4). To our knowledge, there are only seven previously reported cases of epithelioid sarcoma of the orbit (6).

Histologically distinctive features are: prominence of the epithelioid cell component, a sheet-like growth pattern of large cells with vesicular nuclei and prominent nucleoli, and a frequent rhabdoid morphology (6). Proximal type epithelioid sarcomas can show a typical granuloma-like pattern. Occasionally, a pseudo-angiomatous architecture may be present.

Immunohistochemically, irrespective of the tumor types, the proximal-type epithelioid sarcomas are clearly epithelial-like, with cytokeratin and EMA commonly present. These tumors show cell membrane-based reactivity for EMA. Just over half of proximal type epithelioid sarcoma express CD34, which is an important factor in distinguishing them from carcinomas, which are virtually always CD34-negative.

In conclusion, proximal type epithelioid sarcoma is an extremely rare tumor of the orbit, with a well characterized histology and immunohistochemistry. It is difficult to treat in the head and neck region and the associated mortality rate is high. Aggressive surgical therapy with intensive follow-up is recommended. The prognosis depends on the resection status.

Submitted to the 11th Arkadi M. Rywlin symposium by Franco Fedeli, Malpighi Pathology Academy, Florence, Italy.

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  1. J Laskowski, “Sarcoma aponeuroticum,” Nowotwory, 11, 61 (1961).
  2. FM Enzinger, “Epithelioid sarcoma: A sarcoma simulating a granuloma or a carcinoma,” Cancer,  26, 1029 (1970).
  3. DR Chase, FM Enzinger, “Epithelioid sarcoma. Diagnosis, prognostic indicators, and treatment,” Am J Surg Pathol, 9, 241 (1985).
  4. T Hasegawa et al, “Proximal-type epithelioid sarcoma: A clinicopathologic study of 20 cases,” Mod Path, 14, 655 (2001). PMID: 11454997.
  5. L Guillou et al, “‘Proximal-type’ epithelioid sarcoma, a distinctive aggressive neoplasm showing rhabdoid features,” Am J SurgPathol, 21, 130 (1997). PMID: 9042279.
  6. VA White et al, “Epithelioid sarcoma of the orbit,” Ophthalmology, 101, 1680 (1994). PMID: 7936567.
About the Authors
Mohan Narasimhamurthy

Instructor, Breast Pathology Service, Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania

Kumarasen Cooper

Professor of Pathology and Laboratory Medicine, Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania

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