Table of Contents
Definition / general | Pathophysiology | Clinical features | Prognostic factors | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Molecular / cytogenetics description | Differential diagnosis | Additional referencesCite this page: Mammary type myofibroblastoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/vulvamtmyofibroblastoma.html. Accessed July 16th, 2017.
Definition / general
- Initially described in the breast, myofibroblastoma occurs in a wide range of anatomic locations
- It rarely involves the lower genital tract, predominantly vagina (less commonly vulva and cervix)
Pathophysiology
- History of exogenous hormone or tamoxifen exposure has been documented in some cases
Clinical features
- Age of presentation ranges from 23 to 80 years
- Most patients complain of a mass
Prognostic factors
- Benign behavior with no recurrences or death after conservative excision
Treatment
- Local excision is curative
Gross description
- Well circumscribed mass, sometimes polypoid
- Rubbery and whorled cut surface
Microscopic (histologic) description
- Tumor is well demarcated, without a capsule, and with a sharp interface with the overlying dermis
- Tumor contains haphazardly oriented fascicles of bland spindle cells
- Interspersed matrix is composed of hyalinized collagen bundles
- A variable adipose tissue component is commonly seen
Positive stains
- Estrogen receptor and progesterone receptor (>95%)
- Desmin (90%), CD34 (68%)
Negative stains
Molecular / cytogenetics description
- Monoallelic loss of FOXO1 / FOX1A1 on 13q14 has been demonstrated in mammary and vulvovaginal myofibroblastoma (Hum Pathol 2012;43:1887)
Differential diagnosis
- Cellular angiofibroma: morphologic overlap and similar genetic findings (both have loss of FOX1A1 at 13q14), but cellular angiofibroma has a more prominent vascular component and lacks thick hyalinized collagen bundles
- Angiomyofibroblastoma: areas of hypo- and hypercellularity, more prominent vascular component (delicate capillary-sized vessels), CD34 negative
- Aggressive angiomyxoma: prominent myxoid change with hypocellularity; lacks intersecting fascicles and thick hyalinized collagen bundles
- Metastatic adenocarcinoma from gastrointestinal tract origin: signet ring cells
Additional references


