Aspiration cytology of the collagenized variant of mammary myofibroblastoma: a case report with review of the literature

Epithelioid myofibroblastoma with concurrent presentation of LCIS and DCIS

Myofibroblastoma (MFB) of the breast is a rare benign neoplasm of the mammary stroma. Several morphologic variants have been described in the literature, which can create diagnostic challenges for pathologists, in particular the epithelioid variant of MFB, which can mimic invasive lobular carcinoma. We report a case of a 72-year-old female who presented for a painless breast lump and was later found to have 2 lesions on imaging, with 1 lesion corresponding to the palpable lump and the other lying in a different quadrant. Core-needle biopsies demonstrated ductal carcinoma in-situ at both lesional sites with what was originally felt to be an invasive lobular carcinoma at the lesional site which did not correspond to the palpable lump. After mastectomy, with more complete visualization microscopically of the lesional area originally felt to be an invasive lobular carcinoma, the final pathology was consistent with a MFB, predominantly epithelioid variant, in addition to ductal carcinoma in-situ and lobular carcinoma in-situ. In this paper we describe the imaging findings of an epithelioid MFB and how its nonspecific nature necessitates close communication between the radiologist and pathologist to make the correct diagnosis.

Mammary Myofibroblastoma: Report of a Case and Review of the Literature

Mammary myofibroblastoma is a benign mesenchymal tumor composed of fibroblasts, myofibroblasts, and a variable number of adipocytes. Mammary myofibroblastoma usually occurs in men of older age and is less common in postmenopausal women. It may also happen in extramammary sites along the milk line. In this instance, it is referred to as mammary-type myofibroblastoma. Rarely multifocal and bilateral tumors have been described. Clinically and radiologically, it can be misinterpreted as a malignant tumor due to its rarity. Size usually does not exceed 3 cm. The diagnosis requires clinicopathological correlation with morphological and immunohistochemical evaluation, especially in limited biopsy specimens. We herewith describe a rare case of mammary myofibroblastoma in a 37-year-old female patient. We also review the literature focusing on the potential differential diagnostic issues and discuss this tumor's ultrastructural and cytogenetic findings.

A case of mammary myofibroblastoma diagnosed with cytomorphological, cell block and immunohistochemistry findings

Myofibroblastoma (MFB) is a rare benign spindle cell tumor originating from myofibroblasts in the breast stroma. MFB typically presents as a slow-growing, well-circumscribed, solitary mass ranging from 1 to 4 cm in size. It has been reported in adults, and frequently seen in older males and in postmenopausal females. The lesion is composed of stromal cells showing fibroblastic and myofibroblastic differentiation at the morphological, immunohistochemical and ultrastructural levels. To date, the literature includes only about 24 MFB cases confirmed via fine-needle aspiration and cytological evaluation. Here, we present a patient with MFB that was diagnosed via conventional smear slides and cell block, in addition to immunohistochemical analysis.

Cytological Features of Palisaded Mammary-Type Myofibroblastoma

Palisaded mammary-type myofibroblastoma is a rare variant of benign stromal spindle cell tumor whose histological features are well known. Nevertheless, no cytological features have been reported to date. In this article, we describe the cytological features of a case of palisaded mammary-type myofibroblastoma in which a preoperative fine needle aspirate was obtained. Smears were moderately cellular, characterized by clusters of spindle cells, disposed in a parallel fashion and immersed in myxoid background. Although the lesion is rare, it is worth distinguishing from benign and malignant spindle cell tumors.

Mammary Myofibroblastoma: A Tumor With a Wide Morphologic Spectrum

Context.—Myofibroblastoma (MFB) of the breast is an unusual benign tumor that belongs to the family of the “benign spindle cell tumors of the mammary stroma.” The name MFB reflects its cellular composition, comprising mainly stromal cells with fibromyofibroblastic and, less frequently, myoid differentiation. Since the original description, the morphologic spectrum of MFB has been expanded by the recognition of several unusual morphologic variants, such as the cellular, infiltrative, epithelioid, deciduoid-like, lipomatous, collagenized/fibrous, and myxoid variants.

Objective.—To review the literature on mammary MFB, discussing the main clinical, radiologic, and pathologic features helpful for diagnosis. Since MFB may show alarming morphologic features, which can lead to a misdiagnosis of malignancy, histologic figures of this tumor, including its more unusual variants, are provided to offer pathologists a practical approach to a correct diagnosis. Histogenesis and pathogenesis of this tumor are also proposed.

Data Sources.—Clinicopathologic data on MFB were extracted from all identified articles through PUB Medline– based research. Histologic figures have been taken from the personal archive of the author.

Conclusions.—The incidence of MFB diagnosis has increased in recent years, likely due to the mammographic screening. Accordingly, this unusual benign tumor may represent a potential diagnostic pitfall, especially when interpreting fine-needle aspiration and/or needle core biopsy. Pathologists should be aware of the wide morphologic spectrum exhibited by MFB to avoid a misdiagnosis of malignancy.

Breast spindle cell tumours: about eight cases

Background

Breast spindle cell tumours (BSCTs), although rare, represent a heterogeneous group with different treatment modalities. This work was undertaken to evaluate the utility of fine needle aspiration cytology (FNAC), histopathology and immunohistochemistry (IHC) in differentiating BSCTs.

Methods

FNAC of eight breast masses diagnosed cytologically as BSCTs was followed by wide excision biopsy. IHC using a panel of antibodies against vimentin, pan-cytokeratin, s100, desmin, smooth muscle actin, CD34, and CD10 was evaluated to define their nature.

Results

FNAC defined the tumors as benign (n = 4), suspicious (n = 2) and malignant (n = 3), based on the cytopathological criteria of malignancy. Following wide excision biopsy, the tumors were reclassified into benign (n = 5) and malignant (n = 3). In the benign group, the diagnosis was raised histologically and confirmed by IHC for 3 cases (one spindle cell lipoma, one myofibroblastoma and one leiomyoma). For the remaining two cases, the diagnosis was set up after IHC (one fibromatosis and one spindle cell variant of adenomyoepithelioma). In the malignant group, a leiomyosarcoma was diagnosed histologically, while IHC was crucial to set up the diagnosis of one case of spindle cell carcinoma and one malignant myoepithelioma.

Conclusion

FNAC in BSCTs is an insufficient tool and should be followed by wide excision biopsy. The latter technique differentiate benign from malignant BSCTs and is able in 50% of the cases to set up the definite diagnosis. IHC is of value to define the nature of different benign lesions and is mandatory in the malignant ones for optimal treatment. Awareness of the different types of BSCTs prevents unnecessary extensive therapeutic regimes.

Mammary myofibroblastoma: Report of two cases with fine-needle aspiration cytology and review of the cytology literature

Fine-needle aspirates from two histologically, immunohistochemically, and ultrastructurally confirmed mammary myofibroblastomas (MM) of two elderly women revealed abundant, randomly arranged single and clustered benign spindle-shaped mesenchymal cells with scant cytoplasm and elongated or oval nuclei displaying a finely granular chromatin pattern and inconspicuous nucleoli. In one case a few cells showed inconspicuous nuclear grooves. The aspirated tumor cells from the other case stained positively with desmin and CD34 antibodies and negatively with cytokeratin and S-100 protein antibodies, in keeping with an MM. A review of the literature was briefly presented.