Benign-appearing Lesions Research Articles

Morphological, dynamic and functional characteristics of liver pseudolesions and benign lesions.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide and one of the most common causes of death among patients with cirrhosis, developing in 1-8% of them every year, regardless of their cirrhotic stage. The radiological features of HCC are almost always sufficient for reaching the diagnosis; thus, histological confirmation is rarely needed. However, the study of cirrhotic livers remains a challenge for radiologists due to the developing of fibrous and regenerative tissue that cause the distortion of normal liver parenchyma, changing the typical appearances of benign lesions and pseudolesions, which therefore may be misinterpreted as malignancies. In addition, a correct distinction between pseudolesions and malignancy is crucial to allow appropriate targeted therapy and avoid treatment delays.The present review encompasses technical pitfalls and describes focal benign lesions and pseudolesions that may be misinterpreted as HCC in cirrhotic livers, providing the imaging features of regenerative nodules, large regenerative nodules, siderotic nodules, hepatic hemangiomas (including rapidly filling and sclerosed hemangiomas), segmental hyperplasia, arterioportal shunts, focal confluent fibrosis and focal fatty changes. Lastly, the present review explores the most promising new imaging techniques that are emerging and that could help radiologists differentiate benign lesions and pseudolesions from overt HCC.

Role of MRI in Differentiating Various Posterior Cranial Fossa Space-Occupying Lesions Using Sensitivity and Specificity: A Prospective Study

Background: Any abnormal space-occupying posterior fossa lesion may directly involve the vital structures like the brain stem, cranial nerves, cerebellum, vertebrobasilar artery, and venous sinuses, which makes the surgical approach and total excision very difficult. Hence for these reasons, precise evaluation of posterior fossa lesion with MRI is a must to visualize the vital structures, which helps in planning and safe surgery. Objective: This study aimed to evaluate the added value of diffusion-weighted imaging and magnetic resonance spectroscopy in the localization, extension, characterization, differentiation of various posterior fossa space-occupying lesions, and correlating with the histopathological result.Materials and methods: This prospective study comprised of 40 patients who were suspected with posterior fossa space-occupying lesions on basis of clinical features or on CT scan. All patients were evaluated using conventional as well as newer MRI techniques using Siemens 1.5 Tesla MRI scanner (Siemens Medical System, Erlangen, Germany). Diffusion-weighted imaging (DWI) was done in all patients and magnetic resonance spectroscopy (MRS) was done in 27 patients. Based on the MRI findings, various posterior fossa lesions were classified as neoplastic or non-neoplastic. The neoplastic lesions were further classified as benign and malignant. The MRI findings were correlated with histopathological findings or follow-up.Statistical analysis: Independent sample t-test was used to compare the mean apparent diffusion coefficient (ADC) values of various posterior fossa space-occupying lesions. Receiver operating characteristic (ROC) curve analysis was done to determine the optimal cut-off mean ADC values and choline/creatinine (Cho/cr) ratios for various benign and malignant posterior fossa tumors.Results: Of 40 patients with posterior fossa lesions, 23 were males and 17 were females with a mean age of 34.67±1.93[SD] years. Metastases were the most common posterior fossa lesions in our study sample and found in seven patients (17.5%) followed by vestibular schwannomas and brainstem gliomas in five patients (12.5%) each, demyelinating lesion in four patients (10%), tubercular abscess in three patients (7.5%), hemangioblastoma, tuberculoma, arachnoid cyst, epidermoid cyst, pilocytic astrocytoma, low-grade glioma in two patients (5%) each, meningioma, medulloblastoma, pyogenic abscess and high-grade glioma in one patient (2.5%) each. The mean ADC value of benign tumors was higher than that of malignant tumors and this difference was found to be significant (p = 0.019). The cut-off ADC value 1.022 x 10-3mm2/s had a sensitivity of 78.6% and specificity of 66.7%. MRS played important role in differentiating neoplastic from non-neoplastic lesions and benign from malignant tumors. The cut-off Cho/cr ratio of 1.25 had a sensitivity of 66.7%, specificity of 85.7% to differentiate benign from malignant tumors.Conclusion: Conventional MRI sequences able to diagnose most of the benign-appearing lesions of posterior fossa, however, adding advanced MRI sequences like diffusion-weighted imaging and MR spectroscopy helps us to differentiate and diagnose various posterior fossa lesions even closer to the actual histopathological diagnosis.

Cutaneous cystic lesions: its clinicopathological correlation with emphasis on unusual findings.

Background: Cutaneous cysts are the most common lesions encountered in surgical practice withcosmetic and psychological concern to the patient. Aim: To establish the clinicopathologicalcorrelation of these lesions and also the importance of histological evaluation for the prevention ofmisdiagnosing a benign-appearing malignant lesion. Methods: A retrospective descriptive studywith data collected from archives of histopathology from January 2018 to December 2020 ofclinically diagnosed cutaneous cyst along with age, gender, location and histopathological evaluationwere analysed. Results: 88 cases that were clinically diagnosed as cutaneous cysts had a higherfemale proportion 52.3%. The most common clinical diagnosis is epidermal/ sebaceous cyst. 35.2%of cases were clinically diagnosed accurately but 64.8% of cases did not correlate with clinicaldiagnosis. 4 malignant lesions were misdiagnosed as benign cutaneous cyst clinically. Conclusion:Most often clinically diagnosed cutaneous cysts are not sent for histopathological evaluation which isa very important tool to confirm the diagnosis.

Abstract B42: The cell adhesion molecule, L1CAM, is important for the dissemination and metastasis of fallopian tube precursor lesions

Abstract One of the hallmarks during the progression of high-grade serous ovarian cancer (HGSOC) is the dissemination and metastasis of cells from fallopian tube precursor lesions, namely serous tubal in situ carcinoma (STIC), to other sites of the fallopian tube, ovary, or peritoneal cavity. We, and others, have previously demonstrated that HGSOC originates from benign-appearing lesions in the fallopian tube, harboring TP53 mutations (P53 signatures), that progress into STIC lesions, and show an increase in DNA damage and proliferation. While studies have analyzed those precursor lesions at the distal end of the fallopian tube, little is known about the mechanism that triggers the dissemination of cells from fallopian tube precursor lesions to other sites. The L1 cell adhesion molecule (L1CAM, CD171) has been shown to play an important role in many types of cancer, including ovarian carcinoma. In vitro studies have shown that L1CAM enhances proliferation, cell migration, epithelial-to-mesenchymal transition (EMT), and chemoresistance in ovarian carcinoma cells. In HGSOC, high expression of L1CAM is associated with poor overall survival and confers chemoresistance in this setting. It was further shown that L1CAM expression and the presence of its soluble form in ovarian carcinoma patient ascites correlates with shorter patient survival. Current knowledge is limited on the role of L1CAM during the initiation or the early stages of HGSOC. Therefore, we investigated precursor STIC lesions for L1CAM expression. We found expression of L1CAM in most of the analyzed STIC lesions, but also in scattered normal fallopian epithelial cells. Interestingly, the expression in STIC lesions was not homogenous but showed a gradient with its lowest expression in cells attached to the basement membrane and its highest expression in pseudo-stratified cells that appear to be in the process of detaching. To investigate whether L1CAM contributes to detachment, we used the CRISPR/CAS9 system to knock down L1CAM in the ovarian cancer cell line OVCAR8. Importantly, the knockdown of L1CAM decreased the ability of cells to grow and survive under anchorage-independent culture conditions and to build 3-dimensional spheres. Conversely, overexpression of L1CAM in primary fallopian tube cells led to a strong increase in their ability to form spheres. We found that the expression of L1CAM in ovarian cancer and primary fallopian tube cell lines led to an increase in integrin alpha-5 and integrin beta-1 expression. This ultimately leads to an increased recruitment and organization of fibronectin and assembly of a basement membrane under anchorage-independent culture conditions. These data indicate that in precursor lesions L1CAM expression may be necessary for the tumor to disseminate and metastasize to other sites of the fallopian tube, ovary, or peritoneal cavity. Finally, we found a strong link between the noncanonical WNT pathway and L1CAM expression, which might explain the high L1CAM expression at the apical side of the STIC lesions. However, further studies must be performed to analyze which factors regulate the expression gradient of L1CAM and whether the inhibition of those factors or L1CAM itself delay the onset of the malignant disease. Citation Format: Kai Doberstein, Marcin Iwanicki, Mina Fogel, Peter Altevogt, Ronny Drapkin. The cell adhesion molecule, L1CAM, is important for the dissemination and metastasis of fallopian tube precursor lesions. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr B42.

Context-aware stacked convolutional neural networks for classification of breast carcinomas in whole-slide histopathology images.

Currently, histopathological tissue examination by a pathologist represents the gold standard for breast lesion diagnostics. Automated classification of histopathological whole-slide images (WSIs) is challenging owing to the wide range of appearances of benign lesions and the visual similarity of ductal carcinoma in-situ (DCIS) to invasive lesions at the cellular level. Consequently, analysis of tissue at high resolutions with a large contextual area is necessary. We present context-aware stacked convolutional neural networks (CNN) for classification of breast WSIs into normal/benign, DCIS, and invasive ductal carcinoma (IDC). We first train a CNN using high pixel resolution to capture cellular level information. The feature responses generated by this model are then fed as input to a second CNN, stacked on top of the first. Training of this stacked architecture with large input patches enables learning of fine-grained (cellular) details and global tissue structures. Our system is trained and evaluated on a dataset containing 221 WSIs of hematoxylin and eosin stained breast tissue specimens. The system achieves an AUC of 0.962 for the binary classification of nonmalignant and malignant slides and obtains a three-class accuracy of 81.3% for classification of WSIs into normal/benign, DCIS, and IDC, demonstrating its potential for routine diagnostics.

Value of diffusion-weighted MRI in evaluation of solid hepatic focal lesions in patients with renal insufficiency

ObjectivesTo evaluate the diagnostic accuracy of diffusion weighted MRI in diagnosis of solid hepatic focal lesions in patients with impaired renal functions. Patients and methodsThis prospective study included (30) patients with impaired renal function and had solid hepatic focal lesions based on ultrasound examination. All patients subjected to diffusion MRI examination and ADC measurement, and the data obtained were compared with histopathological results of malignant lesions and previously reported appearance of benign lesions. ResultsThere were 57 solid focal lesions in the included 30 patients. The mean ADC value of hemangiomas was 2.03×10−3, lipoma was 0.1×10−3, HCC was 1.06×10−3 and for metastases was 1.2×10−3. Benign lesions have significant higher ADC values than malignant ones (p=0.003), and in malignant lesions the primary hepatic carcinomas had lower ADC values compared to metastatic lesions which had no significant value. Using a cutoff value of 1.6×10−3 for the ADC to differentiate between benign and malignant lesions the AUC was 90% with Sensitivity, Specificity, PPV, NPV and accuracy of 92%, 80%, 98%, 50% and 91% respectively. ConclusionDW-MRI and ADC value measurements are effective in characterizing solid focal hepatic lesions without contrast injection in patients with renal impairment.

Malignant Skin Tumor Misdiagnosed as a Benign Skin Lesion.

Despite the fact that benign skin lesions can undergo malignant transformation, the necessity and timing of the surgical resection have yet to be established. In this study, we analyse three cases of benign-appearing skin lesions, which were found to be carcinomatous on histologic examination and review the literature regarding the importance of prophylactic removal of benign-appearing skin lesion. The first and second cases were female patients wishing for cosmetic surgery. The first patient had a benign-appearing lesion on dorsum nasi, and the second patient had an inconspicuous lesion right along the right nasolabial fold. The third patient was a middle-aged male with a pigmented lesion on the left cheek, who presented to the clinic only after having met the operating surgeon through an acquaintance outside the hospital setting. All of the lesions were suspected to be of benign nature and were excised for cosmesis only. However, histologic examination of these lesions showed that the first two tumors were basal cell carcinoma with the last tumor being squamouse cell carcinoma. Thus, it is considered that removal of benign like skin lesion will result in good prognosis of patients scheduled to undergo other surgery.

Synchronous bilateral breast carcinomas with divergent radiographic presentations: Radiologic–pathologic correlation of invasive mucinous and ductal carcinomas

The differential diagnosis of well-circumscribed breast masses on imaging includes mostly benign tumors. A potential pitfall in diagnostic breast imaging is that 10–20% of malignancies appear as lesions with benign imaging characteristics. This report presents a case of synchronous bilateral breast masses, one of which demonstrated benign imaging characteristics (well circumscribed) and the second of which demonstrated suspicious imaging characteristics (spiculated and indistinct). After radiologic–pathologic correlation, it was found that the well-circumscribed mass of the right breast was an invasive mucinous carcinoma, and the spiculated indistinct mass of the left breast was an invasive ductal carcinoma. This highlights a possible hazard of diagnostic imaging in the setting of benign-appearing lesions, and underscores the importance of radiographic–pathologic correlation in the evaluation of breast masses.

Plasmablastic lymphoma of the oral cavity in an undiagnosed HIV-positive patient

Plasmablastic lymphoma is an HIV-associated non-Hodgkin's lymphoma that has a known effect on the oral cavity and jaws. A case is presented of oral plasmablastic lymphoma in an apparently medically well 38 year old male. The patient presented with a large mass fungating from the upper left second molar socket, 2 weeks following extraction. The presence of an exophytic soft tissue lesion in a socket shortly after extraction is an infrequent occurrence. Such lesions should be investigated appropriately as malignant lesions may clinically mimic the appearance of benign lesions.

Clinical review: Thyroid cancer mimics on surveillance neck sonography.

Sonography of the neck is a critical tool in monitoring patients after near-total thyroidectomy for differentiated thyroid cancer. Sonography has proven to be among the most sensitive imaging techniques for the detection of recurrent or residual cancer in the thyroidectomy bed and metastatic cervical lymph nodes. It is important for the sonologist to be familiar with normal postsurgical findings and other disease processes that may imitate malignant lesions. We describe the typical sonographic appearance of benign lesions that can resemble recurrent thyroid cancer.

Local recurrence of breast cancer in reconstructed breasts using TRAM flap after skin-sparing mastectomy: clinical and imaging features.

To evaluate clinical and imaging features of cancer recurrence in reconstructed breasts following skin-sparing mastectomy (SSM) or nipple areolar skin-sparing mastectomy (NASSM). This study was approved by our Institutional Review Board. In this retrospective study, we included patients with pathologically confirmed recurrent cancer who had transverse rectus abdominis myocutaneous (TRAM) flap reconstruction after SSM or NASSM and whose follow-up radiological studies were available. Each patient's demographic data, imaging studies and clinical outcomes were reviewed. Two breast radiologists analysed the imaging findings of follow-up mammography, ultrasound and magnetic resonance imaging. Of the 964 patients, 16 (1.7%) had local cancer recurrence. The average follow-up period until the detection was 31.1 months (range, 7-84 months). Fourteen (87.5%) patients had recurrence on the skin or in subcutaneous fat. Of the 16 patients, recurrence was detected by breast self-examination in 13 (81.3%) patients. Eight (50%) lesions mimicked benign lesions. The other eight (50%) lesions manifested various degree of suspicion for the malignancy. Recurrent cancer after TRAM flap reconstruction following SSM and NASSM is often recognised by breast self-examination and mimics imaging findings of benign lesions. Therefore, meticulous physical examination and history-taking are important. Pathological confirmation is worthwhile even in the benign-appearing lesions. Overview of clinical and imaging features of cancer recurrence in reconstructed breasts. 50% of recurred malignant lesions mimicking imaging findings of benign lesions. Patients may benefit from thorough self-breast examination.

Appearance of breast cysts in planar geometry photoacoustic mammography using 1064-nm excitation

In the search for improved imaging modalities for detection and diagnosis of breast cancer, a high negative prediction value is also important. Photoacoustic (optoacoustic) imaging is a relatively new technique that has high potential for visualizing breast malignancies, but little is known about the photoacoustic appearance of benign lesions. In this work, we investigate the visibility of benign breast cysts in forward-mode photoacoustic mammography using 1064-nm light, as currently applied in the Twente photoacoustic mammoscope. Results from (Monte Carlo and k-wave) simulations and phantom measurements were used to interpret results from patient measurements. There was a strong agreement among the results from simulations, phantom, and patient measurements. Depending on the absorption contrast between cyst and breast tissue, cysts were visible as either one or two confined high-contrast areas representing the front and the back of the cyst, respectively. This edge enhancement is most likely the consequence of the local sudden change in the absorbed energy density and Grüneisen coefficients. Although the current forward-mode single-wavelength photoacoustic mammoscope cannot always unambiguously discriminate cysts from malignancies, this study reveals specific features of cysts compared to malignancies, which can be exploited for discrimination of the two abnormalities in future modifications of the imager.

Imaging-Guided Biopsy of 18F-FDG–Avid Extrapulmonary Lesions: Do Lesion Location and Morphologic Features on CT Affect the Positive Predictive Value for Malignancy?

The purpose of our study was to analyze the effect of lesion location and morphologic appearance on CT on the positive predictive value (PPV) for malignancy of all extrapulmonary lesions that were (18)F-FDG avid on PET/CT and that were biopsied under imaging guidance. Between January 2004 and December 2010, 227 patients underwent imaging-guided biopsy of 231 PET-positive extrapulmonary lesions with diagnostic pathologic results. The PET PPV for malignancy was retrospectively calculated and stratified according to lesion location and morphologic appearance. The overall PET PPV for malignancy was 72%. Inflammatory processes accounted for the majority of benign biopsy results. Lesion location significantly affected the PPV (p < 0.001). Bone (96%) and liver (90%) lesions had significantly higher PPVs for malignancy compared with other locations, whereas lymph nodes (60%) had a significantly lower PPV for malignancy. Lesions that were morphologically suspicious and morphologically benign according to CT findings alone were associated with PPVs of 74% and 57%, respectively (p = 0.05). FDG-avid subcentimeter lymph nodes (n = 8) had a PPV for malignancy of 38%. Over half of PET-avid morphologically benign-appearing lesions and one third of PET-avid subcentimeter lymph nodes were found to be malignant at biopsy, suggesting that benign morphologic appearance alone should not preclude further workup of a PET-positive lesion. Biopsies of FDG-avid lesions in liver and bone yielded high rates of true malignancy, whereas biopsies of lymph nodes yielded a lower rate of malignancy compared with other lesion locations.

Ewing sarcoma of the tibia mimicking fibrous dysplasia

Ewing sarcoma (ES) family of tumors is the second most common primary bone malignancy in children. It usually presents as an aggressive looking lesion often located in the meta-diaphyseal region of long bones, with bone destruction, permeation, cortical thinning and/or destruction, periosteal reaction, and large soft-tissue mass. The purpose of this study is to illustrate the occurrence of a fibrous dysplasia (FD)-appearing ES of the tibia. These cases underscore the potential difficulties encountered in the diagnosis of ES. In this study, we performed a retrospective review of children who presented with an otherwise benign-appearing lesion of the tibia, suggestive of FD, which proved to be ES after biopsy. As a result, all patients presented with a history of indolent lower extremity pain of several months of duration, without significant swelling or constitutional symptoms. Plain films revealed an otherwise benign-appearing/FD-like lesion without bone destruction and mild cortical thinning, little or no periosteal reaction. Magnetic resonance imaging revealed the intramedullary extension of the lesion without significant cortical or periosteal involvement and no soft tissue mass. Lesions were hypointense on T1-weighted imaging and hyperintense on T2-weighted imaging. All patients underwent open incisional biopsy and after cytogenetic and molecular studies, the diagnosis of ES was confirmed. We conclude that ES is a deadly malignant tumor if left untreated or if mismanaged. Although it usually presents as an aggressive-looking lesion, at times it may mimic FD and has a benign-looking appearance, making the diagnosis unlikely and challenging. Summation of these cases demonstrates that the potential reasons for misdiagnoses include a low level of suspicion, an atypical site occurrence, a benign radiographic appearance, and a lack of or insufficient histologic specimens.

Milia-like idiopathic calcinosis cutis of the medial canthus

Calcinosis cutis is a term used to describe a group of disorders in which calcium deposits form in the skin and may be classified as dystrophic, metastatic, idiopathic or iatrogenic calcification, and calciphylaxis. Idiopathic calcinosis cutis occurs without any underlying tissue damage or metabolic disorder. In this paper, the authors report a new case of idiopathic calcinosis involving the medial canthus of the left eye that was mistaken for milia. An 18-year-old previously healthy male patient, presented with an asymptomatic whitish solitary tumour of the medial canthus of the left eye. The patient had no systemic or trauma history, and the serum levels of calcium and phosphorous were normal. An excisional biopsy was performed and histopathologic examination revealed subepidermal calcinosis. Calcinosis cutis is a rare condition that should be included in the differential diagnosis of a benign-appearing lesion of the face. While it can occur in patients with a history of inflammation, trauma, or hypercalcemia, its etiology can also be idiopathic.

Intraosseous schwannoma of the proximal femur

A schwannoma is a benign nerve sheath tumor commonly located in soft tissue. An intraosseous schwannoma is very rare, and only four cases involving the femur were found in a review of the English-language medical literature. We present a rare case of a schwannoma with well-defined, lytic, dumbbell-shaped and benign-appearing lesions of the proximal femur.

The Natural History of Gastrointestinal Subepithelial Tumors Arising From Muscularis Propria

The majority of lesions originating from muscularis propria of stomach, duodenum, and colon are gastrointestinal stromal tumors (GISTs). Surgery is indicated when endosonographic criteria of malignancy are met, but little is known about the natural history of lesions with benign endosonographic features. Aim of this study was to evaluate the natural course of benign-appearing lesions originating from muscularis propria in organs where GISTs significantly overcome leiomyomas. A total of 49 asymptomatic patients with hypoechoic lesions originating from the fourth layer of the gastrointestinal tract entered a follow-up program by means of endoscopic ultrasonography. All lesions were nonulcerated, <3 cm in maximal diameter, with regular margins, and cystic spaces of <3 mm. After a mean follow-up of 31+/-20.8 months and a median of 2 (range, 1 to 5) endosonographies/patient, no change in echostructure or dimensions was seen in 44 subjects whereas in 5, an increase of at least 25% in 1 diameter occurred. Surgical removal was proposed to all: 1 patient refused (she is still alive and symptom-free after 4 y), 3 of the 4 lesions removed proved to be GISTs with very low or low risk of malignancy and 1 lesion was classified as a glomus tumor with no malignant appearance. Even small and benign-appearing lesions from muscularis propria may increase in size over time but this increase cannot be considered as an index of malignancy. As most of these lesions are GISTs, a policy of surveillance is advisable.

Idiopathic Equinocavovarus Foot Deformity in an 8-year-old Girl

Idiopathic Equinocavovarus Foot Deformity in an 8-year-old Girl

Pathology Quiz Case

A 70-YEAR-OLD WOMAN PRESENTED WITH A 3-year history of a large left nasal mass as well as associated unilateral nasal obstruction and rhinorrhea. Her medical history was notable for a nasal polypectomy 20 years earlier. Physical examination revealed that the mass completely filled the left nasal cavity, expanding the ala and protruding beyond the left nasal vestibule. Indirect examination showed a large mucosalcovered lesion filling the left nasopharynx. Bone window coronal sections of a maxillofacial computed tomogram demonstrated a mass filling the left nasal cavity from the anterior naris to the posterior choana, with remodeling of the nasal cavity (Figure 1). Biopsy revealed a benign-appearing lesion with evidence of chronic sinusitis, and the patient was scheduled for operative resection. During surgery, the firm, fibrous, and minimally vascular mass was found to be attached to the inferior turbinate by a narrow pedicle (Figure 2). Histopathologic examination of the specimen at low power revealed a polypoid mass with “leaflike” invaginations of the surface respiratory mucosa (Figure 3, top right) and stroma containing cystic dilated ducts with a haphazard assortment of seromucous glands embedded in fibrocollagenous stroma (Figure 3). At higher power, bland plump spindle cells with surrounding collagenized to focally myxoid stroma were observed in association with a proliferation of these erratically arranged cytologically bland seromucous glands (Figure4). The stroma contained very few thin-walled blood vessels. Small numbers of mast cells were present throughout the stroma; however, only minimal patchy chronic inflammation was present. These mononuclear inflammatory cells were associated with only some of the dilated ducts. The surface mucosa and dilated ducts were not associated with thickened basement membranes. What is your diagnosis?

Pathological Correlation of Re-excised Breast Lesions after the use of the Ultrasound-Guided Vacuum-Assisted Biopsy Device (Mammotome®)

�biopsy is a relatively new surgical technique that is a minimally invasive image-guided procedure, requiring a small incision that produces a barely noticeable scar. The technique is a useful method for the surgical biopsy of properly selected patients. We reviewed the pathology of the biopsies for the proper selection of a mammotome biopsy in patients with re-excised breast tumors. Methods: During a 24-month period, we performed vacuumassisted breast biopsies for 277 likely benign breast lesions using ultrasound and fine-needle aspiration cytology or a core needle biopsy, in 203 patients. The age of the patients ranged from 15 to 67 yr (average age 36.6 yr), and the average size of the lesions was 2.39 ±1.06 cm (minimum size 0.5 cm, maximum size 5.0 cm). We retrospectively analyzed the pathological findings of the re-excised breast lesions. Results: The pathology of ultrasound-guided vacuum biopsies of the benign-appearing breast lesions were fibroadenomas (69.7%), intraductal papillomas (6.1%), fibrocystic disease (7.9%), phyllodes tumors (2.9%), malignant tumors (1.4%), ductal hyperplasia (2.9%), and other benign diseases (9.1%). Re-excision by a conventional method was performed for nine patients. Reasons for re-excision were the presence of five proven malignancies (a malignant phyllodes tumor in 2 cases, a tubular carcinoma in 1 case, a papillary carcinoma in 1 case and a ductal carcinoma in situ [DCIS] in 1 case), a possible atypical ductal hyperplasia (ADH) malignancy, two marginal involvement in phyllodes tumors and the possible extension of a lesion as an atypical papilloma. In the re-excised specimens, residual tissues were noticed in eight cases. An ADH lesion was proven as a DCIS. Conclusion: A case of suggested marginal involvements and/or a possible malignancy should be re-excised because of the high possibility of remnant lesions being present after the mammotome biopsy. The cytological and pathological review must be performed precisely before performing the mammotome procedures with considering of the clinical and radiological findings.