J Breast Cancer.  2019 Jun;22(2):326-335. 10.4048/jbc.2019.22.e30.

Solitary Fibrous Tumor of Breast with Anaplastic Areas (Malignant Solitary Fibrous Tumor): A Case Report with Review of Literature

• Jung MJ
• Alrahwan D
• Dubrovsky
• Baek D
• Ayala AG
• Ro JY

• KMID: 2450125
• DOI: http://doi.org/10.4048/jbc.2019.22.e30

Abstract

Solitary fibrous tumor (SFT) is a rare, soft tissue neoplasm that rarely presents in breast tissue, with only 27 previously reported cases. To our knowledge, only one case of malignant SFT has been reported in the English literature. A 75-year-old Caucasian woman presented to our institution with a 3-month history of a palpable left breast mass. No other symptoms, including nipple discharge or skin changes, were noted. She underwent 3 previous biopsies for right breast masses, all of which were benign, with no evidence of spindle cell neoplasm, atypical hyperplasia, or malignancy. Microscopic examination of the mass demonstrated a classic area of SFT with areas of high-grade anaplastic component. In these areas, the tumor showed atypical epithelioid cells arranged in hypercellular sheets with diminished branching vasculature, nuclear pleomorphism, and increased mitotic count (up to 9/10 high-power fields). This case represents the second case of malignant SFT in the breast.

Keyword

Hemangiopericytoma; CD34; Dedifferentiation; Malignant; STAT6

MeSH Terms

Aged
Biopsy
Breast*
Epithelioid Cells
Female
Hemangiopericytoma
Humans
Hyperplasia
Nipples
Skin
Soft Tissue Neoplasms
Solitary Fibrous Tumors*

Figure

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  Figure 1 Radiologic findings (A) Ultrasound showing a highly vascular, oval, circumscribed, and hypoechoic mass in the left breast at posterior depth causing mass effect on the pectoralis muscle posteriorly. (B) Mammogram shows an oval, circumscribed, and obscured mass in the left breast at posterior depth abutting the pectoralis muscle. This mass contains a single benign-appearing coarse calcification.

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  Figure 2 Microscopic findings (A) Well demarcated tumor border; however, it is focally permeative into the surrounding adipose tissue and skeletal muscles (arrows). (B) Tumor cells are arranged haphazardly with alternating cellularity (hypocellular on left and hypercellular on right) and prominent vasculature. (C) Hypocellular area is composed of bland looking, plump spindle or oval tumor cells. (D) Hypercellular area with compact sheet-like arrangement (left side) is transited from classic tumor areas (right side). (E) Hypercellular area is composed of pleomorphic tumor cells with increased mitotic figures (hematoxylin and eosin stain; (A) ×50, (B) ×100, (C) ×400, (D) ×100, and (E) ×400).

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  Figure 3 Tumor cells positive for cluster of differentiation 34 (A), signal transducer and activator of transcription 6 (B), B-cell lymphoma 2 (C) negative for cytokeratin (D), S100 (E), and p63 (F) (×200).

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  Figure 4 Immunohistochemical findings in hypercellular and pleomorphic areas cluster of differentiation 34 (A), B-cell lymphoma 2 (B), and signal transducer and activator of transcription 6 (C). Immunoreactivity shows the same staining pattern and intensity as in classic areas (×200).

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