Nodular fasciitis of the breast simulating breast cancer on imaging

Nodular Fasciitis of the Breast Mimicking Phyllodes Tumors: A Case Report and Literature Review

Nodular fasciitis is a benign proliferative lesion of the fibroblasts and/or myofibroblasts, generally detected in the soft tissue of the upper extremities. It has also been reported in the lower extremities, head, and neck, and rarely in the breast. Its rarity and nonspecific clinical and radiological features resemble those of malignant tumors of the breast and make the differential diagnosis and management difficult. Herein, we present a rare case of nodular fasciitis of the breast, which was initially suspected to be a phyllodes tumor.

Low to Intermediate (Borderline) Grade Breast Spindle Cell Lesions on Needle Biopsy: Diagnostic Approach and Clinical Management

Spindle cell proliferations of the breast are a heterogeneous group of lesions ranging from benign or reactive lesions to aggressive malignant neoplasms. Diagnosis on core biopsy can be particularly challenging as lesions displaying different lineages associated with variable outcomes share overlapping morphologies (scar vs. fibromatosis-like metaplastic carcinoma) whereas individual entities can exhibit a large variety of appearances (myofibroblastoma). In this review, lesions are grouped into lineage, when possible, including those showing fibroblastic/myofibroblastic differentiation, ranging from entities that require no additional management, such as scar and nodular fasciitis, to those with unpredictable clinical outcomes such as fibromatosis and solitary fibrous tumor or locally aggressive behavior such as dermatofibrosarcoma protuberans. The review of low-grade vascular lesions includes atypical vascular lesion and low-grade angiosarcoma. Also discussed are various adipocytic lesions ranging from lipoma to liposarcoma, and rare smooth muscle and neural entities more commonly encountered in locations outside the breast, such as leiomyoma, neurofibroma, schwannoma, or granular cell tumor. Optimal histological evaluation of these entities merges clinical and radiologic data with morphology and ancillary testing. We present our approach to immunohistochemical and other ancillary testing and highlight issues in pathology correlation with imaging. Recent updates in the management of breast spindle cell lesions are addressed. In a well-sampled lesion with radiographic concordance, the core biopsy diagnosis reliably guides management and we advocate the inclusion of management recommendations in the pathology report. Precise characterization using up to date guidelines is important to identify a subset of patients who may safely avoid unnecessary surgical procedures. A multidisciplinary approach with close collaboration with our clinical colleagues is emphasized.

Nodular fasciitis of the breast: clinicopathologic and molecular characterization with identification of novel USP6 fusion partners

Nodular fasciitis is a benign, self-limited, pseudosarcomatous neoplasm that can mimic malignancy due to its rapid growth, cellularity, and mitotic activity. Involvement of the breast is rare and diagnosis on biopsy can be challenging. In this largest series to date, we examined the clinicopathologic and molecular characteristics of 12 cases of nodular fasciitis involving the breast/axilla. All patients were female, with a median age of 32 years (range 15-61). The lesions were 0.4 to 5.8 cm in size (median 0.8). All cases presented as palpable masses, and two patients had overlying skin retraction. Microscopically, lesions were relatively well-circumscribed nodular masses of bland myofibroblastic spindle cells within a variably myxoid stroma. Infiltrative growth into adipose tissue or breast epithelium was frequent. Mitotic figures were present in all cases, ranging from 1 to 12 per 10 high-power fields (median 3). Immunohistochemically, all cases expressed smooth muscle actin and were negative for pan-cytokeratin, p63, desmin, CD34, and nuclear beta-catenin. Targeted RNA sequencing performed on 11 cases identified USP6 gene fusions in eight; one additional case was positive by break-apart fluorescence in situ hybridization. The common MYH9-USP6 rearrangement was detected in four cases; another case had a rare alternative fusion with CTNNB1. Three cases harbored novel USP6 gene fusions involving NACA, SLFN11, or LDHA. All fusions juxtaposed the promoter region of the 5' partner gene with the full-length coding sequence of USP6. Outcome data were available for eight patients; none developed recurrence or metastasis. Five patients elected for observation without immediate excision, and self-resolution of the lesions was reported in three cases. Albeit uncommon, nodular fasciitis should be considered in the differential diagnosis of breast spindle cell lesions. A broad immunohistochemical panel to exclude histologic mimics, including metaplastic carcinoma, is important. Confirmatory detection of USP6 rearrangements can aid in classification, with potential therapeutic implications.

Spindle cell lesions of the breast: a diagnostic approach

Spindle cell lesions of the breast comprise a heterogeneous group of lesions, ranging from reactive and benign processes to aggressive malignant tumours. Despite their rarity, they attract the attention of breast pathologists due to their overlapping morphological features and diagnostic challenges, particularly on core needle biopsy (CNB) specimens. Pathologists should recognise the wide range of differential diagnoses and be familiar with the diverse morphological appearances of these lesions to make an accurate diagnosis and to suggest proper management of the patients. Clinical history, immunohistochemistry, and molecular assays are helpful in making a correct diagnosis in morphologically challenging cases. In this review, we present our approach for the diagnosis of breast spindle cell lesions, highlighting the main features of each entity and the potential pitfalls, particularly on CNB. Breast spindle cell lesions are generally classified into two main categories: bland-appearing and malignant-appearing lesions. Each category includes a distinct list of differential diagnoses and a panel of immunohistochemical markers. In bland-appearing lesions, it is important to distinguish fibromatosis-like spindle cell metaplastic breast carcinoma from other benign entities and to distinguish fibromatosis from scar tissue. The malignant-appearing category includes spindle cell metaplastic carcinoma, stroma rich malignant phyllodes tumour, other primary and metastatic malignant spindle cell tumours of the breast, including angiosarcoma and melanoma, and benign mimics such as florid granulation tissue and nodular fasciitis.

The Rare Benign Lesion That Mimics a Malignant Tumor in Breast Parenchyma: Nodular Fasciitis of the Breast

We herein report the clinical and pathological findings of a rare case of nodular fasciitis in the breast parenchyma of a 48-year-old female. Because of potentially malignant findings on ultrasonography and during clinical examination, the patient underwent an excisional biopsy. Histologically, the lesion was composed of spindle to round shaped cells arranged in short bundles in a storiform pattern. Immunohistochemically, the cells were positive for vimentin and SMA and negative for desmin, S100, and CD34. Based on these morphological and immunohistochemical features, a diagnosis of nodular fasciitis was made. We emphasize that nodular fasciitis of the breast may show clinical features and imaging findings similar to those of breast cancer. The histopathologic diagnosis of nodular fasciitis can also be challenging. The purpose of this case report is to highlight the characteristics and the differential diagnosis of this rare neoplasm.

Nodular fasciitis of the breast in an elderly woman

Nodular fasciitis is a benign proliferation of fibroblasts and myofibroblasts most commonly found in the soft tissues of the upper extremities and the trunk of young to middle-aged adults. Nodular fasciitis is infrequently encountered in the breast and in the elderly. We report a case of a 69-year-old woman presenting with a palpable breast mass with imaging features that mimicked malignancy. Knowledge of this entity is important to allow proper radiological and pathologic concordance and patient management.

An approach to the diagnosis of spindle cell lesions of the breast

Although most breast spindle cell lesions (BSCLs) are rare, they constitute a wide spectrum of diseases, ranging from reactive processes to aggressive malignant tumours. Despite their varied histogenesis and behaviour, some lesions show an overlap of morphological features, making accurate diagnosis a challenging task, particularly in needle core biopsies. Clinical history and immunohistochemistry can help in making a correct diagnosis in morphologically challenging cases. To make an accurate diagnosis, it is important to maintain a wide differential diagnosis and be familiar with the diverse morphological appearances of these different entities. BSCLs can generally be classified into bland-looking and malignant-looking categories. In the former, the commonest diagnosis is scarring. However, it is important to distinguish low-grade spindle cell metaplastic breast carcinoma from other benign entities, as the management is clearly different. In the malignant category, it is important to differentiate metaplastic carcinoma from other malignant primary and metastatic malignant spindle cell tumours of the breast, such as malignant phyllodes tumour, angiosarcoma, and melanoma. This review focuses on the classification and histological and molecular diagnosis of various BSCLs, with an emphasis on the diagnostic approach, including in core biopsies.

Breast Nodular Fasciitis: A Comprehensive Review

BACKGROUND

This article describes the demographic, clinical, pathological and prognostic features of breast nodular fasciitis through a comprehensive review of the cases reported in modern literature.

MATERIAL AND METHODS

English-language articles published from January 1970 to October 2015 and related to breast nodular fasciitis were non-systematically retrieved using the PubMed database. Titles, abstracts and references were evaluated in order to include the most relevant studies. The demographic characteristics of the patients and the signs and symptoms of the disease were reviewed, as well as the results of the radiological and diagnostic procedures employed and of the treatments adopted.

RESULTS

26 papers reporting on 28 cases were enrolled; however, manuscripts published before 1990 were excluded because of old methodologies, technologies and clinical approaches. Thus, 22 cases included in 20 papers were analyzed in detail.

CONCLUSION

The rarity and the unspecific clinical and radiological characteristics of breast nodular fasciitis make the differential diagnosis and management challenging. Knowledge of the clinical, pathological and prognostic aspects of this condition is crucial for breast care specialists in order to improve their diagnostic and therapeutic interventions.

Nodular Fasciitis of the Breast

Nodular fasciitis of the breast is a rare benign pathology of soft tissue that is a consequence of fibroblastic hyperplasia within breast. It can mimic breast cancer clinically, radiologically, and histopathologically.

A-43 year-old female with a painless mass within upper-lateral quadrant of her left breast complained of rapid and progressive growth during previous few days. No evidence of nipple discharge or sensation of pain was expressed. The mass was tender to palpation, but the size was too tiny to detect. The definitive diagnosis was established with sonography, which detected a hypoechogenic lesion, 10 mm in diameter. The excisional biopsy delivered a tissue composed of fusiform fibroblastic cells with bright ellipsoid-like nuclei and elevated nucleolus. Mitotic formations were also obvious. Low cellular and high cellular zones with hyaline fibrosis and erythrocyte accumulation existed, as well as a light lymphocytic infiltration. All of these features, in addition to adipocytic accumulation within the margins of this lesion, suggested a definitive diagnosis of Nodular fasciitis. The diagnosis of nodular fasciitis is difficult and often is indiscriminable from breast cancer, so paying close attention to this matter is critical.

A spontaneously resolving breast lesion: imaging and cytological findings of nodular fasciitis of the breast with FISH showing USP6 gene rearrangement

We report a case of nodular fasciitis of the breast in a 48-year-old woman who presented with a tender rapidly growing right breast lump. Ultrasound guided fine needle aspiration (FNA) of the solid mass was performed. Cytology was reported as atypical spindle cell neoplasm and the patient was referred to a breast surgeon at a tertiary institution for a definitive diagnosis and further management. Follow-up ultrasound showed partial regression and MRI, mammogram after 2-3 weeks confirmed spontaneous and total resolution of the lesion. Nodular fasciitis of the breast is rarely diagnosed on cytology alone and a histological diagnosis is usually required for a definitive diagnosis. However, in this case, the lesion spontaneously resolved prior to core biopsy or diagnostic open biopsy. The cytological features in conjunction with immunohistochemistry and the clinical history strongly suggest nodular fasciitis, which is further supported by a USP6 FISH positive result.

Nodular fasciitis of the breast mimicking breast cancer

Nodular fasciitis is a benign proliferative lesion that is usually found in the soft tissue of the upper extremity and trunk in young to middle-aged persons. It has rarely been described in the breast. A 35-year-old woman had noticed a mass in her left breast. It was elastic-hard, 13 mm in size, and located mainly in the upper inner quadrant of the left breast. Mammography did not detect the mass. Ultrasonography revealed a hypoechoic lesion with an irregular margin. Neither fine-needle aspiration cytology nor core needle biopsy established a definitive diagnosis. Excisional biopsy was therefore performed. Histologically, the excised tumor tissue results were consistent with a diagnosis of nodular fasciitis of the breast. We report a case of nodular fasciitis of the breast, a rare histological type of breast tumor.

Nodular fasciitis in the axillary tail of the breast

Nodular fasciitis is a benign proliferation of myofibroblasts which presents clinically as a rapidly growing mass with nonspecific features on imaging and high cellular activity on histopathology. Nodular fasciitis can be mistaken for malignant fibrous lesions such as soft tissue sarcoma or breast carcinoma when located within breast tissue. This presents a problem for appropriate treatment planning as the natural history of nodular fasciitis is spontaneous regression. We present the mammographic, sonographic, computed tomography, and histopathologic characteristics of nodular fasciitis in a 68 year female initially presenting with a rapidly enlarging right axillary mass.

Nodular fasciitis of the breast: two cases with a review of imaging findings

Nodular fasciitis of the breast is a rare, benign, proliferative disease characterized by sudden onset and rapid growth. It can clinically and radiologically mimic breast cancer. We present imaging findings from two cases of nodular fasciitis that initially manifested as palpable masses. Sonographically, they appeared as irregular, not-circumscribed hypoechoic nodules. The diagnosis of nodular fasciitis was made by US-guided core needle biopsies. US-guided vacuum-assisted excision was subsequently performed in the first case, while the second resolved via spontaneous regression.

Imaging findings for malignancy-mimicking nodular fasciitis of the breast and a review of previous imaging studies

We report a case of nodular fasciitis of the breast mimicking malignant tumor. A 41-year-old female patient with a palpable mass in the upper center of the left breast present for 1 week visited our hospital. A mammogram showed an oval isodense with a partially indistinct margin. Ultrasonography demonstrated a hypoechoic mass, 8 × 11 mm in size. Breast cancer could not be excluded based on mammographic and ultrasonographic (US) findings. A core needle biopsy and excisional biopsy were performed. Histopathologic examination revealed a diagnosis of nodular fasciitis of the breast. The mammographic and US findings of nodular fasciitis in the breast is reviewed.

Myoepithelial and epithelial-myoepithelial, mesenchymal and fibroepithelial breast lesions: updates from the WHO Classification of Tumours of the Breast 2012

In the 4th edition of the WHO Classification of Tumours of the Breast, myoepithelial lesions are retitled myoepithelial and epithelial-myoepithelial lesions in order to better reflect the dual participation of luminal and myoepithelial compartments in some key entities. Malignant myoepithelioma, described as a section within the chapter on myoepithelial lesions in the 3rd edition, is recognised in the 4th edition as part of metaplastic carcinoma. Adenomyoepithelioma with malignancy is categorised in terms of the cellular component undergoing malignant transformation. The list of antibodies that can be used for identifying myoepithelial cells is updated. Among mesenchymal lesions, new additions are nodular fasciitis and atypical vascular lesions, while the haemangiopericytoma is removed. The 3rd edition stated that pathological prediction of behaviour of phyllodes tumours is difficult in the individual case. In the 4th edition, some progress has been made in prioritisation and weighting of histological parameters that can potentially estimate probability of recurrence. The WHO Working Group advocates leaning towards a diagnosis of fibroadenoma in cases where there is histological uncertainty in distinction from a benign phyllodes tumour, or adopting the neutral term 'benign fibroepithelial neoplasm', as the clinical behaviour of fibroadenoma overlaps with that of benign phyllodes tumour. The 3rd edition terminology of 'periductal stromal sarcoma' is revised to 'periductal stromal tumour', akin to the widespread consensus to avoid the use of the term 'cystosarcoma' in the context of phyllodes tumours.

Nodular fasciitis of the breast

Nodular fasciitis of the breast is a rare, benign, soft-tissue tumor that can clinically and radiologically mimic invasive ductal carcinoma. A 25-year-old woman presented with a palpable lesion in the lower inner aspect of the left breast. Radiologically, breast carcinoma could not be excluded. On examination of the core needle biopsy, the tumor was characterized histologically as a spindle cell tumor. Excisional biopsy was performed. The tumor was diagnosed as nodular fasciitis of the breast. The imaging and histological findings of this case are presented.

Nodular Fasciitis of the Breast Previously Misdiagnosed as Breast Carcinoma

BACKGROUND: Nodular fasciitis of the breast is a rare benign pathology that can mimic breast cancer clinically, radiologically, and histopathologically. CASE REPORT: An 18-year-old female patient had first visited a physician in a different center with the complaint of a lump in her left breast. Breast examination had revealed a palpable mass located in the left upper outer quadrant. Ultrasonography had demonstrated a hypoechoic lesion. Excisional biopsy of the lump had been performed and histopathologic examination misdiagnosed this lump as a mesenchymal tumor. The patient was then referred to our clinic for further investigations. Pathologic revision was performed and the diagnosis of nodular fasciitis of the breast was established. CONCLUSION: Awareness of this rare clinical entity, nodular fasciitis, in the breast eliminates the misdiagnosis of breast cancer.

Nodular Fasciitis: Differential Considerations and Current Management Strategies

Nodular fasciitis (NF) typically presents as an enlarging soft tissue mass with imaging characteristics that may be suggestive of soft tissue sarcoma or desmoid tumor. This presentation can make a correct diagnosis and management of patients with NF a challenge. We report our recent experience with two cases of NF that were both referred with a diagnoses of “soft tissue sarcoma.” Patient 1 was a 46-year-old woman who had undergone breast augmentation and was referred with a rapidly growing firm mass on the left chest wall beneath the breast implant. Computed tomography of the chest noted the mass to be 8 cm X 11 cm in size displacing the implant laterally with no radiological involvement of the bony structures of the chest. Core biopsy was suggestive of inflammation only. Given the clinical suspicion of malignancy, the patient underwent resection of the mass with implant removal. Final pathology showed NF. Patient 2 was a 65-year-old woman referred with an enlarging tender 3-cm infraclavicular mass and a clinical diagnosis of “soft tissue sarcoma.” Preoperative biopsy suggested NF. The patient underwent complete excision, which confirmed the diagnosis. These cases highlight the clinical issues associated with management of patients with NF. Current approaches to evaluation, diagnosis, and treatment of NF are discussed.

Nodular fasciitis of the breast

We report a case of nodular fasciitis of the breast, which is a rare histological type of breast tumor. A 41-year-old woman had noticed a mass in her right breast. The mass was elastic-hard, 15 mm x 15 mm in size, and located mainly in the upper outer quadrant of the right breast. Mammography demonstrated an oval dense mass with spiculation. Ultrasonography revealed a hypoechoic lesion, 8 mm x 10 mm in size. Fine needle aspiration cytology and core needle biopsy showed no evidence of malignancy. Excisional biopsy was performed. The tumor was characterized by a proliferation of fibroblastic cells. Histologically, the excised tumor was consistent with nodular fasciitis of the breast. Nodular fasciitis should be considered in the differential diagnosis of a mass suspicious for breast cancer.

Nodular fasciitis of the male breast: a case report

A case of nodular fasciitis is reported that involved the breast parenchyma of a 40-year-old man. The differential diagnosis of nodular fasciitis in the male breast mainly includes fibromatosis and myofibroblastoma. However, other benign and malignant spindle cell lesions of the breast, such as pseudoangiomatous stromal hyperplasia and especially spindle cell metaplastic carcinoma and fibrosarcoma, may enter the differential. The classic histomorphologic features and immunohistochemical findings are helpful in arriving at the correct diagnosis. The patient underwent a total excision of the lesion and is free of disease after 14 months. To our knowledge, this is the first reported case of a lesion of this type in the male breast.

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.

Nodular fascitis in the thigh followed up using ultrasonography

A 41-year-old woman noticed a mass on the inside of her right thigh in April 2003. Ultrasound examination revealed a mass measuring 18 mm × 10 mm × 10 mm in the subcutaneous fatty tissues. Its boundary was relatively clear, with rough edges. The interior of the lesion was hyperechoic and contained an irregular hypoechoic area in its center; a color Doppler sonographic examination detected no blood flow signals. Incision biopsy examination seemed warranted. Pathologically, the specimen showed a proliferation of fibroblast-like spindle-shaped cells but no atypical cells. Immunologic staining revealed that sections were positive to vimentin; negative to CD34, CD68, α-smooth muscle actin (α-SMA), and S-100 protein; and mildly positive to HHF35. These results led to a diagnosis of nodular fascitis. Nodular fascitis is not common, and few studies have described its sonographic characteristics. We therefore used ultrasound to follow up the patient and found that the lesion was markedly smaller 3 months after the first examination, at which time it was hardly discernible as a mass. Here we compare the ultrasound and pathologic findings, and report the results of a bibliographic study.

Benign and malignant spindle cell lesions of the breast

Spindle cell lesions of the breast constitute a wide spectrum of benign and malignant proliferations. Myofibroblasts, normal cellular constituents of the mammary intra- and interlobular stroma, compose many of these lesions, which include reactive proliferations and benign or locally aggressive neoplasms. Because of its morphology, low-grade metaplastic spindle cell carcinoma, "fibromatosis-like" is also considered together with spindle cell lesions of the breast. Although certain of the lesions do not occur commonly, they represent diagnostic challenges. This review outlines the morphology of certain spindle cell lesions of the breast including pseudoangiomatous stromal hyperplasia, reactive spindle cell nodule, nodular fasciitis, myofibroblastoma, primary mammary fibromatosis, and low-grade metaplastic spindle cell carcinoma, "fibromatosis-like." The differential diagnosis and diagnostic work-up of these lesions is discussed, and their clinical treatment and prognosis briefly summarized.

Nodular fasciitis of the breast: a case report

Nodular fasciitis is a soft tissue lesion that in rare instances occurs in the breast. It can clinically and radiologically mimic malignant tumor. We describe a case of nodular fasciitis of the breast in a young woman that was misdiagnosed as phyllodes tumor. The histologic features and a review of the literature are presented. Awareness of such an entity in the breast obviates the need for unnecessary surgical intervention.