Tumors of the uterus are extremely uncommon. Pure lipomas of the uterus are very rare, and only a few cases have been reported. We are presenting a case of a post-menopausal lady, a survivor of right breast cancer who had an 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (18FDG PET/CT) for evaluation of a suspected right lung nodule. The scan was negative for hypermetabolic abnormality. However, a hypodense and non-metabolic lesion was seen in the fundus of the uterus. On subsequent hysterectomy, it was found to be a pure lipoma

Ahmed, Waseem

Fatima, Nosheen

uz Zaman, Maseeh

Zaman, Areeba

Zaman, Sidra

English

eCommons@AKU

eCommons@AKUDepartment of Radiology Medical College, PakistanMarch 2019Pure uterine lipoma on 18FDG PET/CT: rare buteasy to diagnose.Maseeh uz ZamanAga Khan University, maseeh.uzzaman@aku.eduNosheen FatimaAga Khan University, nosheen.fatima@aku.eduWaseem AhmedAga Khan University, waseem.ahmed@aku.eduAreeba ZamanSidra ZamanFollow this and additional works at: https://ecommons.aku.edu/pakistan_fhs_mc_radiolRecommended Citationuz Zaman, M., Fatima, N., Ahmed, W., Zaman, A., Zaman, S. (2019). Pure uterine lipoma on 18FDG PET/CT: rare but easy todiagnose.. Cureus, 11(3), 1-4.Available at: https://ecommons.aku.edu/pakistan_fhs_mc_radiol/346Received 02/11/2019 Review began 03/15/2019 Review ended 03/25/2019 Published 03/27/2019© Copyright 2019Zaman et al. This is an open accessarticle distributed under the terms ofthe Creative Commons AttributionLicense CC-BY 3.0., which permitsunrestricted use, distribution, andreproduction in any medium, providedthe original author and source arecredited.Pure Uterine Lipoma on 18FDG PET/CT:Rare But Easy to DiagnoseMaseeh U. Zaman  , Nosheen Fatima  , Wasim A. Memon  , Areeba Zaman  , Sidra Zaman 1. Radiology, Aga Khan University Hospital, Karachi, PAK 2. Internal Medicine, Dr. Ruth K.M. PfauHospital, Karachi, PAK 3. Miscellaneous, Dow Medical College, Karachi, PAK Corresponding author: Maseeh U. Zaman, maseeh.uzzaman@aku.edu Disclosures can be found in Additional Information at the end of the articleAbstractTumors of the uterus are extremely uncommon. Pure lipomas of the uterus are very rare, andonly a few cases have been reported. We are presenting a case of a post-menopausal lady, asurvivor of right breast cancer who had an 18 F-fluorodeoxyglucose positron emissiontomography/computed tomography (18FDG PET/CT) for evaluation of a suspected right lungnodule. The scan was negative for hypermetabolic abnormality. However, a hypodense andnon-metabolic lesion was seen in the fundus of the uterus. On subsequent hysterectomy, it wasfound to be a pure lipoma.Categories: Obstetrics/Gynecology, Radiology, OncologyKeywords: pure lipoma of uterus, lipomatous tumor of the uterus, 18-fdg pet/ctIntroductionLipomatous tumors of the uterus are very uncommon (incidence: 0.03% - 0.25%) [1] and werefirst described by Lobstein in 1816 [2]. Most reported cases have been of the mixed typecontaining varying amounts of smooth muscle and fibrous elements. Pure lipomas involving theuterine wall are exceedingly rare; the exact incidence is not known as only a few cases havebeen reported thus far in the literature [3]. Because of the pure fatty nature of the tumor,computerized tomography (CT) is considered the diagnostic modality [4]. In current oncologicalpractice, F-18 fluorodeoxyglucose (18FDG)-based positron emission tomography and CT(PET/CT) has become an integral part of management. Lipomas consistently show a low 18FDGuptake (standardized uptake value (SUV) < 2.0) [5], but current literature is silent about thefeatures of a pure lipoma of the uterus using 18FDG PET/CT imaging. We are presenting the firstcase of a pure uterine lipoma found on 18FDG PET/CT imaging of a postmenopausal breastcancer survivor.Case PresentationHerein, we present the case of a 67-year-old female breast cancer survivor who had a rightlumpectomy for ductal carcinoma in 2012. She was clinically asymptomatic. However, a recentCT scan of the chest revealed a subcentimeter soft tissue nodule in the lower lobe of the rightlung which was not appreciable on previous CT lung window films (no soft images wereavailable). It was considered a possible granuloma but an 18FDG PET/CT was recommended forevaluation and surveillance of the nodule. The PET/CT was performed with 10.2 mCi of 18FDGafter 60-minute skull to mid-thigh images were acquired using a low-dose, non-contrastenhanced CT protocol. The scan showed no morphological or functional evidence of tumor in1 1 1 2 3 Open Access CaseReport  DOI: 10.7759/cureus.4334How to cite this articleZaman M U, Fatima N, Memon W A, et al. (March 27, 2019) Pure Uterine Lipoma on 18FDG PET/CT: RareBut Easy to Diagnose. Cureus 11(3): e4334. DOI 10.7759/cureus.4334either breast or hypermetabolic nodal and no hepatic, adrenal, pulmonary, or bony metastases.There was a redemonstration of the subcentimeter ametabolic soft tissue nodule in the lowerlobe of the right lung with minimal infiltrate in the right lung base. The uterine fundusrevealed an 18FDG non-avid hypodense area (Hounsfield unit (HU): -89.9) measuring 40 x 30mm (anteroposterior (AP) and transverse (TV) dimensions) without regional nodes (Figure 1).Based on the image characteristics, it was reported as a lipoma. An uneventful hysterectomywas performed after three weeks on request by the family, and the histopathology revealed apure lipoma.FIGURE 1: 18FDG PET/CT images (a-c: axial; d-f: coronal; g-i:sagittal) showing a well-defined hypodense area (Hounsfieldunit (HU): -89.9) without metabolic activity in the uterinefundus.DiscussionA pure lipoma of the uterus is an exceedingly rare tumor and few cases have been publishedthus far. The first reported case of a pure uterine lipoma on preoperative ultrasound waspublished in 1979 [6] and the authors correctly identified the fatty nature of the tumor butincorrectly reported it as dermoid. The first case of a pure lipoma of the uterus identified on CTscan was reported in 1988 which had well-circumscribed and homogenously hypodenseattenuation parameters (HU: -118) [7]. However, mixed uterine lipomas may mimic fibroidtumors depending upon the contribution of non-lipomatous tissue. Because of these peculiarfeatures, a CT scan is considered as the imaging modality of choice for uterine pure lipomas.Lipomas (white fat tumors) are considered to have consistently low 18FDG uptake in contrast tohibernomas (brown fat tumors), which are usually hypermetabolic, as they are thermogenic andrich in mitochondria [5]. Uterine tumors show a wide spectrum of 18FDG uptake ranging fromlow uptake in benign tumors (some leiomyomas may have high uptake) to intense uptake inmalignant neoplasms [8]. However, the literature is silent about 18FDG PET/CT imaging of purelipoma of the uterus. To the best of our research, this is the first case report revealing the 18FDGPET/CT imaging features of a pure lipoma of the uterus.2019 Zaman et al. Cureus 11(3): e4334. DOI 10.7759/cureus.4334 2 of 4Pure lipomas of the uterus are usually found in post-menopausal women and about 60% areintramural. They are usually asymptomatic but may present with symptoms like pain andbleeding, particularly if associated with uterine leiomyomas. On ultrasonography, these tumorshave an echogenic center due to the fat and are avascular with a hypoechoic rim due tomyometrium in the periphery [9]. On magnetic resonance imaging (MRI), a uterine lipomawould appear as a high signal on T1 and T2 sequences and show signal dropout on fat, thusconfirming the diagnosis [9]. On CT examination, these are classically hypodense with ahyperdense periphery when they are intramural [7]. In this case report, the CT appearance of apure lipoma of the uterus was also similar to the previous report with an ametabolic (18FDGnon-avid) appearance on PET images (hypodense and hypometabolic) as commonly observed innon-uterine pure lipomas. With the increasing use of 18FDG PET/CT in oncology, there arehigh odds of finding more cases of pure uterine lipomas and these characteristic imagingfeatures would help the reporting physicians to make a preoperative diagnosis with higherconfidence.ConclusionsA pure lipoma of the uterus is an exceedingly rare benign tumor, and this first case reportdepicting its appearance on 18FDG PET/CT imaging would certainly help the reporting nuclearphysicians and radiologists to diagnose it with a high level of confidence.Additional InformationDisclosuresHuman subjects: Consent was obtained by all participants in this study. Conflicts of interest:In compliance with the ICMJE uniform disclosure form, all authors declare the following:Payment/services info: All authors have declared that no financial support was received fromany organization for the submitted work. Financial relationships: All authors have declaredthat they have no financial relationships at present or within the previous three years with anyorganizations that might have an interest in the submitted work. Other relationships: Allauthors have declared that there are no other relationships or activities that could appear tohave influenced the submitted work.References1. Loffroy R, Nezzal N, Mejean N, Sagot P, Krausé D: Lipoleiomyoma of the uterus: imagingfeatures. Gynecol Obstet Invest. 2008, 66:73-75. 10.1159/0001274092. Brandfass RT, Everts-Suarez EA: Lipomatous tumors of the uterus; a review of the world'sliterature with report of a case of true lipoma. Am J Obst Gynecol. 1955, 70:359-67.10.1016/S0002-9378(16)37680-33. Chandawale S, Karia KM, Agrawal NS, Patil AA, Shetty AB, Kaur M: Uterine lipoleiomyomaand lipoma: A rare unique case report with review of literature. Int J Appl Basic Med Res.2018, 8:193-95. 10.4103/ijabmr.IJABMR_119_174. Chu CY, Tang YK, Chan TS, Wan YH, Fung KH: Diagnostic challenge of lipomatous uterinetumors in three patients. World J Radiol. 2012, 4:58-62. 10.4329/wjr.v4.i2.585. Kim JD, Lee HW: Intense uptake on F18-FDG PET/CT. Nucl Med Mol Imaging. 2012, 46:218-22. 10.1007/s13139-012-0150-z6. Houser LM, Carrasco CH, Sheehan CR Jr: Lipomatous tumour of the uterus: radiographic andultrasonic appearance. Br J Radiol. 1979, 52:992-93. 10.1259/0007-1285-52-624-9927. Jacobs JE, Markowitz SK: CT diagnosis of uterine lipoma . AJR Am J Roentgenol. 1988,150:1335-56. 10.2214/ajr.150.6.13358. Kitajima K, Murakami K, Kaji Y, Sugimura K: Spectrum of FDG PET/CT findings of uterinetumors. AJR Am J Roentgenol. 2010, 195:737-43. 10.2214/AJR.09.40749. Pathak V, Sukheeja D, Singh RK: Uterine intramural lipoma: a benign but rare entity . Med J2019 Zaman et al. Cureus 11(3): e4334. DOI 10.7759/cureus.4334 3 of 4DY Patil Univ. 2017, 10:384-85. 10.4103/0975-2870.2139312019 Zaman et al. Cureus 11(3): e4334. DOI 10.7759/cureus.4334 4 of 4

Pure uterine lipoma on 18FDG PET/CT: rare but easy to diagnose.

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Pure uterine lipoma on 18FDG PET/CT: rare but easy to diagnose.

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