Five-year follow-up after a single US-guided high intensity focused ultrasound treatment of breast fibroadenoma.

The aim of this study was to evaluate the long-term efficacy of a single ultrasound-guided high-intensity focused ultrasound (US-HIFU) treatment in patients with breast fibroadenoma (FA) in terms of volume and pain reduction as well as palpation findings. From december 2013 until november 2014 27 women with a symptomatic FA were treated in one HIFU-session. Follow-up visits were performed after 7 days, 6 months and 1, 2, 3 and 5 years with clinical examination and ultrasound. One year after the procedure, a core needle biopsy of the residual lesion was offered. There was a significant volume reduction 6 months after HIFU from 1083.10 to 347.13 mm3 (p < 0.0001) with a mean volume reduction ratio (VRR) of 61.63%. Thereafter the FAs showed a further, but no longer significant decrease in size. One patient with an initial incomplete ablation and histologically confirmed persistent vital cells after 1 year showed a strong regrowth after 3 years. Excluding this patient from analysis, the mean VRR at months 12, 24, 36, and 60 was 86.44%, 94.44%, 94.90%, and 97.85%, respectively. Before HIFU, 59.26% of the patients had pain (22.33/100 VAS) which decreased to 6.56/100 after 12 months and remained reduced over the 5 year follow up period. A decrease in palpability from 85.19 to 7.69% was observed within 24 months. A single HIFU intervention let to a substantial reduction in size, pain, and palpability with its most potential effect during the first 12 months. Subsequently, the observed effect remained stable over a 5 year follow up period. Incomplete initial treatment was associated with the risk of regrowth.

Clinical efficacy and safety of ultrasound-guided high-intensity focused ultrasound for breast fibroadenoma: a systematic review and meta-analysis.

OBJECTIVE: The purpose of this systematic review and meta-analysis was to assess the clinical efficacy and safety of ultrasound (US)-guided high intensity focused ultrasound (HIFU) in the treatment of breast fibroadenoma in different studies. METHODS: Studies evaluating the efficacy and safety of US-guided HIFU in the treatment of histologically-proven FA with follow-up outcomes of more than 3 months were searched through MEDLINE/PubMed databases. Volume reduction rate (VRR) and side effects were extracted and compared for further analysis. RESULTS: Of 29 identified articles, 10 studies involving 385 women and more than 545 FAs met the inclusion criteria. The mean VRR at 6 months and 12 months after HIFU was 52.00% and 72.00%. In terms of intraoperative safety, nine studies reported mild to moderate pain, with an average visual analogue scale (VAS) score ranging from 1.60 to 7.10. The most common postoperative side effect associated with HIFU was subcutaneous ecchymosis and less frequent were pain, erythema, and skin pigmentation, most of which disappeared within weeks. No serious side effects were observed. CONCLUSION: S-guided HIFU is an effective and safe noninvasive treatment for breast FA that does not cause serious side effects. Further studies are needed to explore crucial influencing factors of VRR.

Breast development and disorders in children and adolescents.

Breast masses are infrequently encountered in pediatric and adolescent populations. Most breast masses in children are benign entities arising from embryological defects which can be managed once breast development is complete. Diagnostic and management dilemmas arise when fibroepithelial lesions of the breast are seen in clinical practice. Differentiation between a fibroadenoma and a phyllodes tumor is important to guide management. Breast cancer in children under 18 years of age is extremely rare and invasive diagnostic testing and aggressive management is only recommended when clinical suspicion of malignancy is very high. Patient and caregiver counseling plays an important role in the management of these diseases. While adult-onset breast diseases have been studied very closely, there is a dearth of literature on pediatric breast anomalies. This review aims to provide a scoping overview of the available literature on benign, fibroepithelial, and malignant lesions of the breast in pediatric and adolescent populations to help guide physicians and surgeons with decision-making regarding the diagnosis and management of pediatric breast diseases.

Real-world reference scores for EORTC QLQ-C30 and EORTC QLQ-BR23 in early breast cancer patients.

PURPOSE: To deliver patient-reported outcome (PRO) reference data for breast cancer and various other breast diseases to facilitate the interpretation of PRO scores during routine breast cancer treatment. METHODS: To determine reference baseline values for the PRO measures EORTC QLQ-C30 and EORTC QLQ-BR23, PRO data captured in the breast cancer centre at Charité - Universitätsmedizin Berlin from 2016 to 2021 were evaluated. As part of the clinical routine, ambulatory patients were asked to answer a digital survey regarding their medical history, current health status and health-related quality of life using the aforementioned questionnaires prior to their doctor's appointment in the outpatient breast clinic. Adjusted linear and variable dispersion beta regression models were used to compare different diagnosis groups. RESULTS: A total of 3689 patients were included in the digital PRO program, of which 1478 were eligible for this study; 729 had invasive breast cancer or ductal carcinoma in situ, 270 patients were diagnosed with fibroadenoma and 479 patients had other breast diseases such as cysts, mastopathy or abscesses. Overall, patients with breast cancer reported worse scores in almost all domains except for role functioning, sexual functioning and body image. Compared to previously published reference scores for early breast cancer, the current data show a more pronounced impact on perceived emotional and cognitive functioning. CONCLUSION: The results of this study are of high value for the interpretation of PROs and facilitate their use in clinical practice and clinical trials. The scores indicate an urgent need for psychosocial support prior to treatment.

A giant fibroadenoma in a mature woman: diagnosis and treatment in a limited resource environment (a case report).

We report an extremely rare case of a 40-year-old woman with a giant fibroadenoma of 30cm in diameter that was accompanied by ulceration and bleeding. We document the onset, the clinical presentation, as well as the challenge encountered in the diagnosis and managing in a limited resource environment.

Is conservative management of fibroadenomas feasible? 5-year results from the Durban Breast Unit.

BACKGROUND: Fibroadenomas (FAs) usually present in young women and, despite being the commonest benign breast masses, are often excised. This study aimed to assess the results of a conservative management protocol in the setting of dedicated breast clinics to reassess the validity of this conservative approach. METHOD: A retrospective chart review of a prospectively maintained database of the index presentation of patients diagnosed with FAs on triple assessment at the breast clinics of Inkosi Albert Luthuli Central Hospital (IALCH) and Addington Hospital (ADH) was undertaken. Women under 35 years with FA less than 5 cm and agreeable to the 5-year conservative management strategy from 2008 to 2015 were included. Variables assessed over the 5-year study period included adherence to clinic visits and any change in size of the lesion(s). RESULTS: Three hundred and six women were studied. The mean age of presentation was 21.5 years (IQR 12-34), and the mean FA size was 2.43 cm (IQR 0.5-4.8). 72.9% were of African ethnicity. 76.5% had a single FA, and in 16.3%, they were bilateral. 50.7% of patients were lost to follow-up, and 9.6% (n = 25) had spontaneous resolution of their FA. Conservative management of FAs was feasible in only 26.1% of patients. CONCLUSION: Conservative management of FAs over 5 years is not practical in our local setting due to the high patient attrition rate. In those who completed the 5-year observation period, only 1 in 10 patients had complete resolution of their FA.

Management of Pediatric Breast Masses: A Multi-institutional Retrospective Cohort Study.

BACKGROUND: The objective of our study was to describe the workup, management, and outcomes of pediatric patients with breast masses undergoing operative intervention. MATERIALS AND METHODS: A retrospective cohort study was conducted of girls 10-21 y of age who underwent surgery for a breast mass across 11 children's hospitals from 2011 to 2016. Demographic and clinical characteristics were summarized. RESULTS: Four hundred and fifty-three female patients with a median age of 16 y (IQR: 3) underwent surgery for a breast mass during the study period. The most common preoperative imaging was breast ultrasound (95%); 28% reported the Breast Imaging Reporting and Data System (BI-RADS) classification. Preoperative core biopsy was performed in 12%. All patients underwent lumpectomy, most commonly due to mass size (45%) or growth (29%). The median maximum dimension of a mass on preoperative ultrasound was 2.8 cm (IQR: 1.9). Most operations were performed by pediatric surgeons (65%) and breast surgeons (25%). The most frequent pathology was fibroadenoma (75%); 3% were phyllodes. BI-RADS scoring ≥4 on breast ultrasound had a sensitivity of 0% and a negative predictive value of 93% for identifying phyllodes tumors. CONCLUSIONS: Most pediatric breast masses are self-identified and benign. BI-RADS classification based on ultrasound was not consistently assigned and had little clinical utility for identifying phyllodes.

Low-grade ductal carcinoma in situ (DCIS) arising in a fibroadenoma of the breast during 5 years follow-up: A case report.

RATIONALE: Fibroadenoma (FA) is a common type of benign breast tumors but ductal carcinoma in situ (DCIS) rarely arises within this tumor type. PATIENT CONCERNS: This case report presents a non-symptomatic 61-year-old woman with FA that was coincidentally found during a breast cancer screening program performed 5 years ago by her city of residence. She had subsequently been followed-up with mammography and breast ultrasound (US). US showed a slightly enlarged tumor and dynamic magnetic resonance imaging (MRI) indicated malignancy within the FA. DIAGNOSIS: The pathological examination revealed low-grade DCIS within the FA. INTERVENTIONS: The patient underwent a core needle biopsy followed by breast-conserving therapy with sentinel lymph node biopsy and then postoperative radiation therapy. OUTCOMES: Currently, she has been followed-up for 2 years without no signs of recurrence. LESSONS: Careful observation with US followed by dynamic MRI is essential in the early diagnosis of DCIS originating in a FA.

Fibroepithelial Lesions (FELs) of the Breast: Is Routine Excision Always Necessary?

BACKGROUND: When needle core biopsies (NCBs) of the breast reveal fibroepithelial lesions (FELs), excision is often performed to rule out a phyllodes tumor (PT), despite low malignancy rates. Consequently, the natural history of observed FELs is not well described. We analyzed the malignancy risk in excised FELs and the natural history of FELs undergoing active surveillance (AS). METHODS: We retrospectively studied the pathology and imaging records of 215 patients with FELs (n = 252) diagnosed on NCB. Incidence of growth was determined by Kaplan-Meier method. RESULTS: Of 252 FELs, 80% were immediately excised and 20% underwent AS. Of the excised FELs, 198 (98%) were benign: fibroadenoma (FA) or benign breast tissue in 137 (68%), benign PT in 59 (29%), or LCIS in 2 (1%). Borderline PT or malignant lesions were found in 4 (2%). On ultrasound, malignant and borderline PTs were larger than benign lesions [median 3.9 vs 1.3 cm, p = 0.006]. Fifty FELs underwent AS, with a median follow-up of 17 (range 2-79) months. The majority remained stable or decreased in size: at 2 years, only 35% increased in volume by ≥ 50%. Of those tumors undergoing AS that were later excised (n = 4), all were benign. CONCLUSIONS: Almost all FELs (98%) were benign on surgical excision, and the majority undergoing AS remained stable, with benign pathology if later excised. Most FELs on NCB can be safely followed with US, with surgery reserved for patients with FELs that are large, symptomatic, or growing. This could spare most women with FELs unnecessary surgery.

Breast fibroadenomas: a review in the light of current literature.

<br><b>Introduction:</b> Fibroadenomas are one of the most common benign tumors of the breast in the adolescent females accounting for about 2/3^rd of all the breast lumps and more than half of all the biopsied breast lesions. They come into being due to overgrowth of glandular tissue under the influence of hormonal changes that the girls undergo at the time of puberty. Due to the wide prevalence of fibroadenomas and the psychosocial morbidity associated with the finding of a breast mass, it is imperative for physicians treating adolescent patients to be thoroughly familiar and updated with this disease. <br><b>Aim:</b> The article aims at providing a brief review of the classification, presentation, diagnosis, and update on the management of breast fibroadenomas on the basis of recent literature.

Pediatric and Adolescent Surgical Breast Clinic: Preliminary Experience.

STUDY OBJECTIVE: The diagnostic and treatment tools used in breast centers are largely geared to adults, and there is little consideration of the unique characteristics of breast diseases in younger age groups. Herein we report on the preliminary experience of a specialized breast clinic for children and adolescents. DESIGN: Retrospective, observational. SETTING: Pediatric Surgical Breast Clinic of Schneider Children's Medical Center of Israel. PARTICIPANTS: Patients referred to the clinic during the first 18 months of its establishment. INTERVENTIONS AND MAIN OUTCOME MEASURES: Rate of breast masses, rate of malignancy, and types of evaluation and treatment. RESULTS: Forty-seven patients aged 0-19 years were referred. Breast masses were suspected in 23/47 (48.9%) and confirmed using ultrasound in 14/47 (29.7%; mean age, 16.4 years), followed by needle core biopsy in 7. Seven patients had multiple masses. Breast Imaging and Reporting Data System scores ranged from 3 to 4b. All cases were treated as fibroadenomas. Four patients underwent surgery because of a large mass (>5 cm; n = 3) or patient's preference to remove the lump rather than follow-up (n = 1). There were no malignancies. The median time from patient identification of the mass until seeking medical help was 5 months. CONCLUSION: Several findings distinct to this age group were highlighted: high rate of multiple masses, lack of malignancy, and high risk of delayed diagnosis. Care should be taken when using Breast Imaging and Reporting Data System categorization because it was formulated for adults and might be very limited in the adolescent population. Longer-term studies of larger cohorts are planned.

Recurrent giant fibroadenomas with transformation to cystosarcoma phyllodes in a 17-year-old girl: a rare case report from Syria.

BACKGROUND: Fibroadenoma is the most prevalent benign breast lesion that generally affects middle-aged women; it is rare in adolescents and younger children. The transformation into malignancy is not common. However, multiple recurrences of rapidly enlarging fibroadenomas suggest a high possibility of transforming into phyllodes tumors, which are uncommon fibroepithelial lesions that account for 0.3-0.5% of female breast tumors and typically present in premenopausal women. CASE PRESENTATION: We report a case of a 17-year-old Syrian girl who previously had three episodes of recurrence of multiple rapidly enlarging fibroadenomas in her left breast and underwent three operations for complete resection of the lesions. However, a few months later, she was readmitted with multiple large masses in the same breast, and pathological findings confirmed a surprising combination of multiple fibroadenomas for the fourth time with a malignant phyllodes tumor (cystosarcoma phyllodes). The patient underwent lumpectomies followed by adjuvant radiotherapy. Long-term follow-up was recommended. CONCLUSION: Our patient had an extraordinary number of episodes of recurrence at a young age and a rare combination of malignant and benign lesions in the same breast with multiple recurrences. We present her unique, very challenging case with the aim of highlighting the importance of clinical correlation, detailed diagnosis, and careful follow-up.

High intensity focused ultrasound (HIFU) for the treatment of symptomatic breast fibroadenoma.

PURPOSE: The aim of the study was to evaluate the efficacy of high intensity focused ultrasound (HIFU) in the treatment of symptomatic breast fibroadenomas (FA) after 6 and 12 months. MATERIALS AND METHODS: Between December 2013 and November 2014, 27 patients with histologically confirmed FA received one application of HIFU under local anesthesia (NCT02011919). Follow-up visits occurred after 6 and 12 months measuring the FA volume and clinical symptoms. A volume reduction of more than 65% was defined as success. Core needle biopsy (CNB) was offered after 12 months if indistinct residuals were visible on ultrasound (US). RESULTS: A successful reduction in FA volume after 12 months was achieved in 24/27 patients (89%). At baseline 16 patients (59%) had pain, which was resolved in 63% (10/16). All patients were satisfied with the cosmetic related outcome. Twenty-four patients (89%) would repeat the procedure. After 12 months 21 patients with sonographically indistinct residuals underwent a CNB. There were no vital cells in 86%. Three cases showed vital cells of FA. Retrospectively possible reasons in these three cases were an insufficient treatment due to bad visibility and insufficient fixation of the FA during HIFU and/or a too short follow-up time. CONCLUSION: US-guided HIFU is an effective procedure and a minimally invasive alternative for the treatment of breast FA.

Pediatric breast masses: an argument for observation.

BACKGROUND: Pediatric breast masses can be a diagnostic challenge. Nearly all are benign, but there is no consensus on which should be removed. We hypothesized that children with asymptomatic breast lesions can be safely managed nonoperatively. METHODS: We performed a single-institution retrospective review of children (≤18 y) who underwent breast mass excision from 2008 to 2016. Male patients with gynecomastia and those who had needle biopsy without formal excision were excluded. Pearson correlation was used to compare ultrasound and pathologic size. Kruskal-Wallis test was used to compare size and final diagnosis. RESULTS: One hundred ninety-six patients were included (96% female). Mean age was 15 ± 3 y. Most patients (71%) presented with a painless mass. Preoperative ultrasound was obtained in 70%. Pathology included fibroadenoma (81.5%), tubular adenoma (5%), benign phyllodes tumor (3%), benign fibroepithelial neoplasm (0.5%), and other benign lesions (10%). There were no malignant lesions. Ultrasound size had a Pearson correlation of 0.84 with pathologic size (P < 0.0001). There was no association between the size and final diagnosis. CONCLUSIONS: Over 9 y, all pediatric breast masses removed at a single center were benign, most commonly fibroadenoma. Ultrasound was an accurate predictor of size, but large lesions did not necessarily confer a high malignancy risk. Observation is appropriate for asymptomatic breast masses in children. Decision for surgery should be individualized and not based on size alone.

Development of a Management Algorithm for the Diagnosis of Cellular Fibroepithelial Lesions From Core Needle Biopsies.

PURPOSE: Surgical excision is recommended for complete evaluation of cellular fibroepithelial lesions identified from core needle biopsy. The purpose of this study was to determine factors associated with phyllodes tumor among cellular fibroepithelial lesions from core biopsies and develop a scoring system to predict the risk of phyllodes tumor. METHODS: We retrospectively reviewed clinical data of 169 breast lesions that were diagnosed as cellular fibroepithelial lesions from core needle biopsy at the Seoul National University Bundang Hospital between March 2005 and January 2013. The clinical, histopathologic, and radiologic characteristics were compared between phyllodes tumors and fibroadenomas during the final diagnosis after surgical excision. RESULTS: Of the 169 lesions, 17 were observed and 152 were surgically removed. After excision, final pathology revealed 60 (39.5%) fibroadenomas and 92 (60.5%) phyllodes tumors. Multivariate analysis demonstrated that age (≥40 years), stromal overgrowth, and stromal cellularity were independent factors associated with phyllodes tumors. A scoring system was developed based on a multivariate logistic regression model, and the area under the receiver operating characteristic curve was 0.828 (95% confidence interval = 0.763-0.893). CONCLUSION: The scoring system will help clinicians make appropriate treatment for patients with cellular fibroepithelial lesions on core needle biopsy.

Progression of Fibroadenoma to Malignant Phyllodes Tumour in a 14-Year Female.

Phyllodes tumours are uncommon breast tumours which account for less than 1% of all breast neoplasms. High-grade malignant phyllodes tumour is a very rare but aggressive breast malignancy and forms approximately 15-30% of all phyllodes tumours. The transformation of a benign fibroadenoma into a malignant phyllodes tumour in a teenaged female is even rarer. We report here an interesting case of malignant phyllodes tumour in a 14-year female patient who was operated twice previously with the diagnosis of complex fibroadenoma in the same breast. There was a large tumour involving whole of the breast and infiltrating the skin. The patient was operated and total mastectomy was done. Diagnosis was confirmed after histopathological examination and immunohistochemistry of the resected specimen. Patient received adjuvant radiotherapy and there was no recurrence on 6-month follow-up. Owing to the rare occurrence of malignant phyllodes tumour in this age group along with previous operations for complex fibroadenoma, this case is being reported here.

High-intensity focused ultrasound in the treatment of breast fibroadenomata (HIFU-F trial).

BACKGROUND: High-intensity focussed ultrasound (HIFU) is a non-invasive ablative technique utilising the application of high frequency ultrasound (US) pressure waves to cause tissue necrosis. This emerging technology is currently limited by prolonged treatment times. The aim of the HIFU-F trial was to perform circumferential HIFU treatment as a means of shortening treatment times. METHODS: A prospective trial was set up to treat 50 consecutive patients ≥18 years of age. Eligible patients possessed symptomatic fibroadenomata, visible on US. Patients ≥25 years of age required histological confirmation of the diagnosis. Primary outcome measures were reduction in treatment time, reduction in volume on US after 12 months and complication rates. RESULTS: HIFU treatment was performed in 51 patients (53 treatments) with a mean age of 29.8 years (SD 7.2 years) and a diameter of 2.6 cm (SD 1.4 cm). Circumferential ablation reduced treatment times by an estimated 19.9 min (SD 25.1 min), which is a 29.4% (SD 15.2%) reduction compared with whole lesion ablation. Volume reduction of 43.2% (SD 35.4%; p < 0.005, paired t-test) was observed on US at 12 months post-treatment. Local complications completely resolved at 1 month apart from skin hyper-pigmentation, which persisted in nine cases at three months, six cases at 6 months and six at 12 months. CONCLUSION: Circumferential HIFU treatment for breast fibroadenomata is feasible to reduce both lesion size and treatment time. HIFU is a non-invasive alternative technique for the treatment of breast fibroadenomata. ISRCTN registration: 76622747.

The Intact® breast lesion excision system as a therapeutic device for selected benign breast lesions.

The aim of this paper is to evaluate our Unit's initial experience using the Intact breast lesion excision system as a therapeutic excision option for benign or borderline breast lesions, which otherwise would entail open operative excision. The study includes the first 111 patients who underwent therapeutic excision with the intact radiofrequency system between December 2012 and May 2016 performed at the Meirav Center for Breast Health, at the Chaim Sheba Medical Center, Ramat Gan Israel. The indications for the procedure included those patients who have benign, or atypical high risk lesions following a previous core needle biospy (CNB) who would have normally undergone conventional excision biopsy. After reviewing each case separately, we found that the use of the BLES system as a treatment device permitted the avoidance of operations that would have been otherwise indicated, in 98 cases of the total 111 in the cohort (88.3%). Thirteen cases eventually had to undergo surgical excision. In eight cases pathology was upgraded from the initial CNB to invasive or noninvasive carcinoma. Although the INTACT sysytem is most commonly used as an alternative biopsy technique for its diagnostic capabilities, this study assessed its clinical role as a definitive therapeutic excisional modality in selected cases of benign breast disease. It proved valuable in the majority of cases with avoidance of surgery where it was traditionally indicated, (98/111, 88.3%) and as definitive fibroadenoma management in a further 28 patients.

Fibroadenoma in adolescent females after living donor liver transplantation.

Breast FA is the most common breast tumor diagnosed in young women. Female renal transplant recipients on CsA have an increased risk of developing FA. However, reports of FA after LDLT have not been described. Our objectives were to determine the incidence of FA, analyze risk factors for FA, and evaluate treatment strategies in adolescent females after LDLT. A total of 18 female patients aged 10-19 years who underwent LDLT and survived at least one year after transplantation were enrolled in our study. The incidence of FA was 11.1%. To determine pre- or post-transplant conditions that are associated with FA after transplantation, the patients were divided into two groups according to the presence or absence of FA: FA group (n=2) and non-FA group (n=16). There were no differences in mean age at LDLT, mean age at breast evaluation, and mean duration between transplantation and breast evaluation between the two groups. However, there was a difference in the immunosuppressive regimen between the two groups. The FA group was maintained on CsA, whereas the non-FA group was maintained on tacrolimus. CsA might be implicated in FA development in adolescent females after LDLT.

Description of the prevalence, histologic characteristics, concomitant abnormalities, and outcomes of mammary gland tumors in companion rats (Rattus norvegicus): 100 cases (1990-2015).

OBJECTIVE To describe the prevalence, histologic characteristics, concomitant abnormalities, and outcomes for various types of mammary gland tumors in companion rats (Rattus norvegicus). DESIGN Retrospective case series. ANIMALS 100 client-owned rats. PROCEDURES Medical records of companion rats that had an SC mass and were examined at a veterinary teaching hospital between 1990 and 2015 were reviewed. Information regarding the signalment, age at mass detection, reproductive sterilization status, histologic diagnosis of the SC mass, location of the initial and all subsequent SC masses, treatments administered, and clinical outcomes was extracted from each record and summarized. RESULTS 105 SC masses were initially detected in 100 rats. The most prevalent SC mass identified was mammary gland fibroadenoma (56/105 [53%]), followed by mammary gland carcinoma (13/105 [12%]). Overall, 26 of 105 (25%) masses were malignant. Sexually intact males were more likely to have nonmammary SC tumors than sexually intact females. In rats receiving no adjunctive treatment after excision of a mammary gland fibroadenoma (n = 16), a second fibroadenoma was detected 1 to 8 months after initial excision, at a median of 4.5 months after surgery. A concomitant pituitary gland tumor was identified in most rats with mammary gland fibroadenoma (21/28 [75%]) and other types of mammary gland tumors (10/17 [59%]). Fourteen of 35 (40%) rats with mammary gland fibroadenoma had concomitant reproductive tract abnormalities. CONCLUSION AND CLINICAL RELEVANCE Results suggested that, like other species, companion rats with SC masses should undergo a thorough diagnostic workup that includes histologic examination of the excised mass.