Indian Journal of Pathology and Microbiology
Home About us Instructions Submission Subscribe Advertise Contact e-Alerts Ahead Of Print Login 
Users Online: 7233
Print this page  Email this page Bookmark this page Small font sizeDefault font sizeIncrease font size

  Table of Contents    
Year : 2011  |  Volume : 54  |  Issue : 2  |  Page : 391-393
Mammary-type myofibroblastoma of soft tissue

1 Section for Skin Pathology, Department of Cellular Pathology, PathLinks Pathology Services, Lincoln County Hospital, Lincoln, United Kingdom
2 Department of Histopathology, Kings Mill Hospital, Mansfield Road, Sutton in Ashfield, United Kingdom

Click here for correspondence address and email

Date of Web Publication27-May-2011


A 40-year-old woman presented with a 1 year history of a painless, subcutaneous lump on the right buttock. Clinical examination showed an approximately 6 cm large subcutaneous mass covered by apparently normal-looking skin. No inguinal lymphadenopathy was found. The mass was excised with the clinical diagnosis of fibroma. Histologically, the lesion was consistent with mammary-type myofibroblastoma of soft tissue, a very rare, benign mesenchymal neoplasm with myofibroblastic differentiation. After surgical excision she was free of recurrence over a period of 8 months. This article also challenges the theory that suggests the origin of this tumor to be from the embryonic mammary tissue, adding another case of a site other than the milk lines.

Keywords: Extramammary, mammary-type, myofibroblastoma, soft tissue

How to cite this article:
Arsenovic N, Abdulla KE, Shamim KS. Mammary-type myofibroblastoma of soft tissue. Indian J Pathol Microbiol 2011;54:391-3

How to cite this URL:
Arsenovic N, Abdulla KE, Shamim KS. Mammary-type myofibroblastoma of soft tissue. Indian J Pathol Microbiol [serial online] 2011 [cited 2023 Dec 1];54:391-3. Available from:

   Introduction Top

Mammary-type myofibroblastoma (MFB) of soft tissue is a benign mesenchymal neoplasm identical to the breast MFB neoplasm with a reported predilection for older males. Both are circumscribed spindle cell neoplasms exhibiting myofibroblastic differentiation and a hyalinized stroma, usually with a fatty component and prominent mast cells. The former, however, occurs in extramammary sites, mainly in the inguinal/groin area. [1] This rare, soft tissue lesion was initially described in 1987 by Wargotz et al.[2] In the English literature there have been 15 such neoplasms described to date. We report a case of a 40-year-old woman with the lesion on her buttock.

   Case Report Top

A 40-year-old woman presented to the outpatient clinic with a nontender, slow-growing, solitary, mobile lump on her right buttock. It was located in the subcutaneous tissue and had grown to a size of 6 cm over a period of 12 months. The mass was well-circumscribed, firm to elastic, quite mobile, and painless. No local/inguinal lymphadenopathy was present. After preoperative evaluation it was marginally excised with the clinical diagnosis of fibroma.

Macroscopic examination showed a firm to elastic, greyish-whitish, well-circumscribed lump measuring 5.5 × 4 × 4 cm, which was covered by the remnants of adipose tissue [[Figure 1], left]. On sectioning, the cut surface displayed solid, white, whorled tissue with no evidence of necrosis, bleeding, or degeneration [[Figure 1], right]. Grossly, the mass appeared to be a leiomyoma.
Figure 1: Well-circumscribed lump covered by remnants of adipose tissue (left); cut surface shows solid, white, whorled tissue without necrosis, bleeding or degeneration (right)

Click here to view

Microscopy revealed a well-circumscribed but unencapsulated mesenchymal proliferation composed of haphazardly arranged fascicles of spindle to oval cells set in a collagenous stroma [Figure 2]. The spindle cells had inconspicuous nuclei and poorly defined eosinophilic cytoplasm. Mitotic activity was low with no atypical figures. No cytologically atypical or multinucleated cells were featured. Occasionally, fat lobules and scattered mast cells were observed [Figure 3]. The adipocytes did not have scalloped, hyperchromatic nuclei, which are characteristic of lipoblasts. Vessels were not prominent. No degenerative/myxoid changes or necrosis were noticed. No ectopic breast tissue was discovered within the attached remnants of the surrounding adipose tissue. The neoplastic spindle cells demonstrated strong expression of desmin along with CD34 [Figure 4] and estrogen positivity. However, there was no actin, S100, or cytokeratin expression. The features had fulfilled the criteria for the diagnosis of an MFB of soft tissue.
Figure 2: Well-circumscribed, unencapsulated mesenchymal proliferation (H and E, ×40)

Click here to view
Figure 3: Highlighted fat lobules and scattered mast cells (Giemsa, ×100)

Click here to view
Figure 4: Diffuse CD34 positivity, (H and E, ×40)

Click here to view

The patient showed no evidence of recurrence 8 months after the operation and therefore has been discharged from follow-up.

   Discussion Top

This article describes the clinical and pathologic characteristics of a very rare, benign mesenchymal neoplasm with features identical to MFB of the breast. To date, only 15 such tumors have been published in the English literature. [1],[3],[4],[10]

MFB of soft tissue is most common in elderly males in the age group of 35-67 years (median age: 53 years). The lesions measure from 2 to 13 cm (median size: 6 cm). [3] Similarly, breast MFB is predominantly found in males between the ages of 41 and 85 years (median age: 64 years).

MFB is a well-circumscribed neoplasm consisting of slender bipolar spindle cells arranged in fascicles of various sizes and bands of hyalinized collagen that often contain prominent mast cells. [2],[5] The tumor usually has a fatty component that shows marked intralesional and interlesional variability in prominence and occasional cases show smooth muscle differentiation. With electron microscope and immunohistochemistry, the proliferating cells seem most closely related to myofibroblasts. Immunohistochemically, the MFB cells are positive for the markers desmin and variably for CD34. [3] One third of them show actin positivity. [3] Some show variable positivity for androgen and estrogen receptors. [5] These lesions are benign with no recurrence or metastasis after surgical excision.

MFB is a rare soft tissue neoplasm of uncertain histogenesis. The androgen receptor or its ligands are possibly related to the development of MFB of the breast and diagnostically useful in differentiating it from other similar spindle cell lesions. [5] Estrogen receptor may have a similar role in female patients.

The distribution of this tumor, including the breast and extramammary groin/perineal area, may prompt the speculation that it has something to do with the embryonic mammary lines, which extend from mid-axillae to medial groins.

Along these lines, accessory breast tissue may be present with or without associated pathologic breast lesions. [9] Despite this, 3 cases in the McMenamin and Fletcher series (buttock, mid-back, paratesticular), our case (buttock), and recently reported cases in the popliteal fossa, [6] head and neck regions, [7] and the vulva [8] rather question the embryonic mammary line concept.

Here is described a case of an unusual and rare soft tissue neoplasm with histologic and immunohistochemical features identical to myofibroblastoma of the breast. The lesion is usually reported in the inguinal/groin area of an elderly man. [3] This case and the previous 5 reported cases [1],[4],[6],[7],[8] indicate the equal occurrence of this neoplasm among the sexes (3 males and 3 females) and its more varied distribution in sites, including the popliteal fossa, [6] the head and neck region, [7] and the vulva. [8] Other sites include buttock, paratesticular area and groin. This article also challenges the theory that suggests the origin being from embryonic mammary tissue, adding another case of a site other than the milk lines. In a recent to-be-published paper it is suggested that the involvement of 13q14 in some cases, appears to confirm the morphologic suggested link of cellular angiofibroma with spindle cell lipoma and MFB. [10]

In conclusion, more reports are needed to evaluate the age, sex, distribution, pathogenesis, and possible behavior of this rare and unusual mesenchymal neoplasm.

   Acknowledgment Top

We would like to thank Dr Kiran Shahpar Shamim for help in preparation of this manuscript.

   References Top

1.Maggiani F, Debiec-Rychter M, Verbeeck G, Sciot R. Extramammary myofibroblastoma is genetically related to spindle cell lipoma. Virchows Arch 2006;449:244-7.   Back to cited text no. 1
2. Wargotz ES, Weiss SW, Norris HJ. Myofibroblastoma of the breast: Sixteen cases of a distinctive benign mesenchymal tumor. Am J Surg Pathol 1987;11:493-502.   Back to cited text no. 2
3.McMenamin ME, Fletcher CD. Mammary-type Myofibroblastoma of soft tissue: A tumour closely related to spindle cell lipoma. Am J Surg Pathol 2001;25:1022-9.   Back to cited text no. 3
4. Mukonoweshuro P, McCormick F, Rachapalli V, Natale S, Smith ME. Paratesticular mammary-type myofibroblastoma. Histopathology 2007;50:396-7.   Back to cited text no. 4
5. Morgan MB, Pitha JV. Myofibroblastoma of the breast revisited: an etiologic association with androgens? Hum Pathol 1998;29:347-51.   Back to cited text no. 5
6. Scotti C, Camnasio F, Rizzo N, Fontana F, De Cobelli F, Peretti GM, et al. Mammary-type myofibroblastoma of popliteal fossa. Skeletal Radiol 2008;37:549-53.   Back to cited text no. 6
7. Hox V, Vander Poorten V, Delaere PR, Hermans R, Debiec-Rychter M, Sciot R. Extramammary myofibroblastoma in the head and neck region. Head Neck 2009;31:1240-4.   Back to cited text no. 7
8. Diwadkar GB, Barber MD. Vulvar mammary-type myofibroblastoma: A case report. J Reprod Med 2009;54:404-6.   Back to cited text no. 8
9. Rosen PP. In: Breast Pathology. Developmental abnormalities. Philadelphia: Lippincott-Raven; 1997. p. 17-21.  Back to cited text no. 9
10.Flucke U, Han JM, van Krieken, Mentzel T. Cellular angiofibroma: Analysis of 25 cases emphasizing its relationship to spindle cell lipoma and mammary-type myofibroblastoma. Mod Patho 2011;24:82-9.  Back to cited text no. 10

Correspondence Address:
Nebojsa Arsenovic
Section for Skin Pathology, Department of Cellular Pathology, PathLinks Pathology Services, Lincoln County Hospital, Lincoln LN2 5QY
United Kingdom
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0377-4929.81646

Rights and Permissions


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]

This article has been cited by
1 Myofibroblastoma in the Liver: A Case Report and Review of Literature
Mohan Narasimhamurthy, Deepika Savant, Lauren Shreve, Mark A. Rosen, Major Kenneth Lee, Kumarasen Cooper, Emma E. Furth, Paul J. Zhang, Zhaohai Yang
International Journal of Surgical Pathology. 2023; : 1066896923
[Pubmed] | [DOI]
2 Retroperitoneal myofibroblastoma in an 88-year-old male
Shogo Watari, Takaharu Ichikawa, Hiromasa Shiraishi, Takafumi Sakuma, Risa Kubota, Norihiro Kusumi, Tomoyasu Tsushima, Keina Nagakita, Yoko Shinno
IJU Case Reports. 2022;
[Pubmed] | [DOI]
3 Mammary-type myofibroblastoma with infarction and atypical mitosis-a potential diagnostic pitfall: A case report
Yuan-Feng Zeng, Yan-Zhi Dai, Min Chen
World Journal of Clinical Cases. 2022; 10(16): 5343
[Pubmed] | [DOI]
4 Mammary-Type Myofibroblastoma of Perineal Region: A Case Report and Literature Review
?? ?
Advances in Clinical Medicine. 2021; 11(04): 1722
[Pubmed] | [DOI]
5 Mammary-Type Myofibroblastoma: A Report of Two Cases
Soyeon An,Joon Seon Song,Soonchan Park,Jung Won Lee,Kyung-Ja Cho
Journal of Pathology and Translational Medicine. 2016; 50(5): 385
[Pubmed] | [DOI]
6 Mammary-type myofibroblastoma of the right thigh: a case report and review of the literature
Jamshid Abdul-Ghafar,Nasir Ud Din,Zubair Ahmad,Steven D Billings
Journal of Medical Case Reports. 2015; 9(1)
[Pubmed] | [DOI]


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Email Alert *
    Add to My List *
* Registration required (free)  

    Case Report
    Article Figures

 Article Access Statistics
    PDF Downloaded81    
    Comments [Add]    
    Cited by others 6    

Recommend this journal