Abdominal Imaging
ª Springer Science+Business Media, LLC 2010 Published online: 20 October 2010
Abdom Imaging (2011) 36:315–317 DOI: 10.1007/s00261-010-9648-y
Primary hepatic leiomyoma: case report Idoia Santos,1 Carlos Valls,1 David Leiva,1 Teresa Serrano,2 Laura Martinez,1 Sandra Ruiz1 1 2
Department of Radiology, Bellvitge University Hospital, Barcelona, Spain Department of Pathology, Bellvitge University Hospital, Barcelona, Spain
Abstract The patient is a previously healthy 28-year-old woman with incidentally detected focal liver lesion. On CT, the tumor showed brisk arterial enhancement and persistent hyperenhancement on portal and delayed phases. Histological study showed spindle cells without atypia and immunohistochemical study was consistent with leiomyoma. Key words: Leiomyoma—Liver tumor—Hepatic leiomyoma
Primary smooth muscle tumors are uncommon, especially leiomyoma and there are few cases reported in the literature [1, 2]. It is a hypervascular tumor which radiological behavior usually does not allow for a confident presurgical diagnosis. There are some cases related to immunodeficiency, either acquired or congenital, although it has been described in immunocompetent patients. We report the imaging and histological findings in a case of primary hepatic leiomyoma.
Case report A healthy 28-year-old woman was referred to our hospital because of incidental detection of a liver mass during abdominal US performed for evaluation of right upper quadrant pain. She had an unremarkable physical and laboratory evaluation except for increased levels of amylase (145 U/L), lipase (95 U/L), AST (2.36 lkat/L), ALT (3.85 lkat/L), GGT (1.51 lkat/L), FA (2 lkat/L), and CA 19.9 (83 U/mL). Liver US showed a large (7 cm) slightly hypoechoic liver mass in segment VI. Contrast enhanced US demonstrated a marked contrast peripheral enhancement and a persistent enhancement compared to
Correspondence to: Carlos Valls; email:
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the surrounding liver in the portal and delayed phases. At pre-contrast CT the lesion showed low attenuation with some scattered dense areas (Fig. 1A). Contrast-enhanced CT showed brisk heterogeneous enhancement in the arterial phase (Fig. 1B) with tiny scattered low attenuation areas. On portal (Fig. 1C) and delayed phases (Fig. 1D), there was persistent hyperenhancement without wash-out. Imaging findings were not consistent with typical benign lesions such as hemangioma or focal nodular hyperplasia (FNH) or malignant lesions such as hepatocellular carcinoma (HCC) or metastasis. A differential diagnosis including atypical adenoma, peripheral cholangiocarcinoma, or stromal tumor was suggested. As the patient had no relevant history of diseases, US-guided biopsy was performed. Histological specimen disclosed benign mesenchymal proliferation with a small number of spindle cells without necrosis or mitotic figures and with eosinophilic cytoplasm. At immunohistochemical examination, the lesion was negative for CD117 and desmin, with CD34 focally positive. Although it did not show clear positivity to CD34, it was diagnosed as a probable solitary fibrous tumor, ruling out hepatocyte tumors (FNH, adenoma, and HCC). Because of concern of potential degeneration, the patient underwent a surgical resection of segment VI. Intraoperative US did not show any other hepatic nodules. On gross examination, the resection specimen showed a white well-delineated mass of 5.5 9 3.5 9 4.5 cm (Fig. 2A). At histological examination it was also a welldefined mass, with a peripheral fibrous capsule and composed by spindle cells without atypia (Fig. 2B). There were no foci of necrosis nor mitosis. A more exhaustive immunohistochemical study demonstrated reactivity for vimentin and actin. Desmin, CD117, and S-100 were negative. CD34 and Bcl2 were focally positive. Although desmin was negative, the final diagnosis was leiomyoma as actin was positive and the rest of markers were negative or focally positive. The patient had a postoperative period without any incidence. Three years later there is no evidence of tumor recurrence.
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Fig. 1. A Non-contrast CT shows a low attenuation mass in segment VI (arrow). B The lesion shows brisk heterogeneous enhancement in the arterial phase with tiny low attenuation areas within it (arrow). C, D The lesion demonstrates persistent hyperenhancement without wash-out in portal (C) and delayed phases (D).
Discussion Smooth muscle tumors are common in the genitourinary and gastrointestinal tracts. However, leiomyomas and leiomyosarcomas are very rare as a primary hepatic tumor [1, 2]. In 1980 Hawkins [3] proposed some criteria to establish a diagnosis of primary hepatic leiomyoma: the tumor must be composed of leiomyocytes and absence of other leiomyomatous tumors at some other site such as uterus, stomach, or intestines. The origin of hepatic leiomyomas is unclear and they may arise from smooth muscle cells from vessels or even the biliary tree [2, 4, 6]. A higher prevalence in patients with immunosuppression or organ transplantation has been observed. Chadwick [7] studied this kind of tumors in children with AIDS, and he proposed a not casualassociation between smooth muscle tumors and HIV infection. This association may be explained because immunosuppression leads to tumor development, but other reports suggest that it is the infection that causes the tumor [2, 8]. Epstein-Barr Virus has also been involved in a pathogenic mechanism of smooth muscle tumors. There have been reported cases of hepatic leiomyomas in AIDS and transplantation patients, that showed positivity for EBV in the tumor [2, 8, 9]. However, there are also several cases of hepatic leiomyoma in healthy people, as our particular case, for example.
The clinical presentation of hepatic leiomyoma can range from a small asymptomatic lesion to a large hepatic mass that causes abdominal pain [10]. Its clinical behavior is still uncertain as differentiation between leiomyoma and leiomyosarcoma is still difficult. It is based on histological criteria. Dense cellularity, nuclear pleomorphism, degenerative changes, large size, and a high mitotic index, orientate more to a leiomyosarcoma. However, the presence of metastases is the only certain sign of malignancy [1, 2, 9, 11]. There are reported cases of apparently benign leiomyomas that have metastasized [11]. Its apparently slow growth and the fact that it is usually asymptomatic, suggest that they may achieve significant size before metastases occur [8]. Characteristic histological features are similar to the ones described in our case: spindle cell proliferation with elongated nuclei, eosinophilic cytoplasm, no nuclear atypia, hemorrhage or necrosis. In some cases, as well as in ours, a fibrous capsule is described [1, 3, 8]. Immunohistochemical examination demonstrates positive staining for smooth muscle actin. There is variability in positivity for desmin [4, 5, 12] and vimentin [5, 6, 8, 11, 12], which are positive in some cases. In few reported cases, were radiological findings adequately described. Interestingly, imaging findings were very similar in most cases. The lesions were generally described as a markedly hypervascular lesion. There
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Fig. 2. A Gross section of the resection specimen. There is a white mass with well-delineated margins. B Microscopic features of the hepatic leiomyoma in a hematoxylin-eosin stained section, consisting in spindle cells with elongated nuclei and eosinophilic cytoplasm. There is no atypia, mitosis, or necrosis.
was more variability in ultrasound findings, although a hypoechoic appearance was the most frequent [4, 11]. Reported CT features include brisk enhancement in the arterial phase, mainly peripheral and in some cases (as well as ours) a persistent enhancement in portal and delayed phase [10, 12]. On MR, leiomyoma is usually hypointense on T1-weighted images and hyperintense on T2-weighted images. There are some descriptions of isointense or hypointense signal on T2. After administration of contrast material, it usually shows an enhancement pattern similar to CT and no enhancement with liver- specific MR contrast agents [10]. In our case, the CT showed some scattered tiny hypodense areas that were visible in all phases. Some other authors have mentioned a central hypo or avascular area. In the article of Kanazawa [12] it is described as an intratumoral hypodense area in the CT that histologically corresponded to hyalinization changes. In other articles, such as Yoon’s [5], hyalinization is also mentioned as well as Reinertson’s [11]. This last report showed hyperintensity areas on T2 but correlation with histology was not reported. In the few cases reported, imaging examination did not give the final diagnosis of hepatic leiomyoma. Our findings of hypervascularity in all phases associated with tiny scattered hypodense areas seem to be very similar to the findings reported in previous cases and may be useful in suggesting the diagnosis in the right clinical setting. In our experience as well as in previous reports, percutaneous biopsy did not yield significant information. In conclusion, primary hepatic leiomyoma is a rare tumor with a difficult radiological diagnosis. Due to the non-specific radiological findings and uncertain biological behavior, it usually leads to surgical resection. Despite its low prevalence, the results of the few cases reported may suggest relatively typical radiological
findings. Hepatic leiomyomas are hypervascular lesions on CT and MRI, with persistent enhancement in portal and delayed phases without evidence of wash-out. Additionally, in some cases, tiny low attenuation areas probably related to hyalinization may be found. In the right clinical setting (a patient without chronic liver disease or oncological history), this constellation of findings may be helpful in suggesting the diagnosis. References 1. Herzberg AJ, MacDonald JA, Tucker JA, Humphrey PA, Meyers WC (1990) Primary leiomyoma of the liver. Am J Gastroenterol 85(12):1642–1645 (review) 2. Pre´vot S, Ne´ris J, de Saint Maur PP (1994) Detection of Epstein Barr virus in an hepatic leiomyomatous neoplasm in an adult human immunodeficiency virus 1-infected patient. Virchows Arch 425(3):321–325 3. Hawkins EP, Jordan GL, McGavran MH (1980) Primary leiomyoma of the liver. Successful treatment by lobectomy and presentation of criteria for diagnosis. Am J Surg Pathol 4(3):301–304 4. Hollands MJ, Jaworski R, Wong KP, Little JM (1989) A leiomyoma of the liver. HPB Surg 1(4):337–343 5. Yoon GS, Kang GH, Kim OJ (1998) Primary myxoid leiomyoma of the liver. Arch Pathol Lab Med 122(12):1112–1115 6. Belli G, Ciciliano F, Lannelli A, Marano I (2001) Hepatic resection for primary giant leiomyoma of the liver. HPB (Oxford) 3(1):11–12 7. Chadwick EG, Connor EJ, Hanson IC, et al. (1990) Tumors of smooth-muscle origin in HIV-infected children. AMA 263(23): 3182–3184 8. Sclabas GM, Maurer CA, Wente MN, Zimmermann A, Bu¨chler MW (2002) Case report: hepatic leiomyoma in a renal transplant recipient. Transplant Proc 34(8):3200–3202 9. Morel D, Merville P, Le Bail B, et al. (1996) Epstein-Barr virus (EBV)-associated hepatic and splenic smooth muscle tumors after kidney transplantation. Nephrol Dial Transplant 11(9):1864–1866 10. Marin D, Catalano C, Rossi M, et al. (2008) Gadobenate dimeglumine-enhanced magnetic resonance imaging of primary leiomyoma of the liver. J Magn Reson Imaging 28(3):755–758 11. Reinertson TE, Fortune JB, Peters JC, Pagnotta I, Balint JA (1992) Primary leiomyoma of the liver. A case report and review of the literature. Dig Dis Sci 37(4):622–627 (review) 12. Kanazawa N, Izumi N, Tsuchiya K, et al. (2002) A case of primary leiomyoma of the liver in a patient without evidence of immunosuppression. Hepatol Res 24(1):80
