Ann Thorac Surg 2010;89:298-300. doi:10.1016/j.athoracsur.2009.06.062
© 2010 The Society of Thoracic Surgeons
Case Reports
Angiomyolipoma in the Lung Detected 15 Years After a Nephrectomy for Renal Angiomyolipoma
Haruaki Hino, MD*,
Shingo Ikeda, MD,
Ryoji Kawano, MD,
Fumitomo Sato, MD,
Kohei Tagawa, MD,
Tatsuhiro Hoshino, MD,
Toshiya Yokota, MD,
Enjo Hata, MD,
Akiko Fujii, MD,
Masaya Mori, MD
Department of General Thoracic Surgery, Pathology, Mitsui Memorial Hospital, Tokyo, Japan
Accepted for publication June 9, 2009.
* Address correspondence to Dr Hino, Department of General Thoracic Surgery and Pathology, Mitsui Memorial Hospital, Kanda-Izumicho 1, Chiyoda-ku, 101-8643, Tokyo (Email: haruakihino{at}mitsuihosp.or.jp).
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Abstract
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Angiomyolipoma is generally found in the kidney, but is especially rare in the lung. Nine cases of angiomyolipoma in the lung have been reported previously, and in 3 of these patients it was involved with nephrectomy for renal angiomyolipoma. The origination of the tumor was not completely recognized, but lymphangioleiomyomatosis and angiomyolipoma are known to have a common feature. The pathogenesis of angiomyolipoma in the lung has recently been researched in relation with lymphangioleiomyomatosis. We review these case reports of angiomyolipoma in the lung and discuss the clinical features and the generation of these tumors.
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Introduction
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Angiomyolipoma (AML), usually found in the kidney, is generally a benign hamartomatous tumor. Extrarenal AML has been reported in various organs, including the liver, mediastinum, and uterus, but is especially rare in the lung. Recently, AML and lymphangioleiomyomatosis (LAM) were shown to have common morphologic and genetic features. We present a patient with AML in the lung long after the resection of a renal AML and review and compare this patient with nine similar case reports.
A 52-year-old woman presented with a dry cough. Her medical history included a right nephrectomy for renal angiomyolipoma at the age of 36 and left upper lobectomy for pulmonary carcinoid at the age of 38. Chest roentgenogram and computed tomography (CT) imaging showed multiple small nodules in the bilateral lung fields (Fig 1). The possibility of extrapulmonary involvement was ruled out. Laboratory findings indicated no abnormalities.
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Fig 1. (A) A chest roentgenogram shows small multiple nodules in the bilateral lung fields. (B) A 7.5-mm computed tomography scan of the chest demonstrated one of the nodules in S10 in the right lung.
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A CT-guided transthoracic needle biopsy was performed twice, and the results showed only fatty tissue, leading to no particular diagnosis. To make a definite diagnosis and determine the treatment method, a video-assisted thoracotomy was done. Intraoperatively, several yellow, small, elastic hard nodules were seen in the right lung. The nodules were soft, a homogenous yellow color, and were well demarcated from the healthy lung tissue (Fig 2).
Three components were noted, including predominantly mature adipose tissue, epithelioid and spindle cells, and small blood vessels. The appearance was similar to the previous renal AML (Fig 3). Neither cytologic atypia nor mitotic activity was observed. Immunohistochemically, some of the epithelioid cells were positive for the melanocytic cell-specific monoclonal antibody human melanoma black 45 (HMB-45) and 
-smooth muscle actin in both the lung and the kidney AML. These results led to a diagnosis of AML in the lung.
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Fig 3. The nodules contained three components characteristic of mature adipose tissue. Epithelioid and spindle cells and small blood vessels were found (hematoxylin and eosin stain, original magnification x40).
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The patient's postoperative course was uneventful. After 17 months, the multiple nodules in the lungs remain almost completely unchanged.
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Comment
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AML is a benign and hamartomatous lesion containing a mixture of a mature adipose tissue and dilated blood vessels that are surrounded by sheets of well-differentiated smooth muscle cells [1]. AML often originates in the kidney and is complicated with tuberous sclerosis in almost half of the cases. Extrarenal AML may arise from the liver, mediastinum, uterus, spermatic cord, retroperitoneum, spleen, and lung [2]. In the present patient, the AML in the kidney and lung had no malignant characteristics; however, very rare cases of sarcomatous transformation and regional lymph node involvement have been reported [3].
AML in the lung was first reported by Guinee and colleagues [4] in 1995, and since then, 9 such patients have been reported, of which 7 were middle-aged women and 6 had a single pulmonary lesion. Three patients (33%) had a history of a nephrectomy for the renal AML long before the appearance of the pulmonary lesions.
In the present patient, a CT-guided biopsy was performed twice but revealed only fat tissue. A CT-guided biopsy might have been ill advised because it is difficult to make a definite diagnosis when the nodule is less than 2 cm in size and consists of two or more components. Consideration should be given to a possible diagnosis of AML when the patient presents with single or multiple pulmonary nodules, especially those with a history of AML.
To date, the pathogenesis of AML in the lung has not been completely elucidated. AML might originate from the lung tissue itself in a multicentric pattern, partly because the tumor is growing very slowly, the histologic appearance of AML is benign, no invasion to the vessels is detected, and extrarenal AML has been reported in various organs such as the liver, uterus, and spleen. On the other hand, considering the radiographically multimetric analysis, the lack of association with bronchial anatomy is suggestive of metastasis from a systemic source.
The hypothetical course of metastasis was that the manipulation of the tumor during the operation to resect the renal AML released the tumor cells to the lung through blood flow very slowly for a long time. Furthermore, the spindle-type cells positive for HMB-45 and -smooth muscle actin were confirmed in the 1-mm-diameter multiple lesion in the lung tissue, thus histologically demonstrating that the AML in the lung was a metastatic tumor.
The spindle and epithelioid cells in the lung were known as a benign metastasizing leiomyoma and pulmonary LAM. LAM cells and AML have common features and belong to the same group of tumors. LAM cells are divided into the subgroup of large and small spindle cells and epithelioid cells. Some of these cells resemble AML and are positive for HMB-45 and -smooth muscle actin. LAM and AML have a very common gene lesion, and LAM cells could originate from the smooth muscle cells of renal AML through the blood flow, which could clarify the cause of AML in the lung [5].
At 1.5 years after the lung biopsy, the tumors in the present patient remain almost the same size. Although in other patients such tumors were stable for longer than 10 years, long-term close observations are still required in this patient for any recurrence of AML originating from organs other than the lung.
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References
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- Enzinger FM, Weiss SW. Soft tissue tumors3rd ed.. St Louis: Mosby; 1995. pp. 405-409.
- Kasuno K, Ueda S, Tanaka A, et al. Pulmonary angiomyolipoma recurring 26 years after nephrectomy for angiomyolipoma: benign clinical course Clin Nephrol 2004;62:469-472.[Medline]
- Ferry JA, Malt RA, Young RH. Renal angiomyolipoma with sarcomatous transformation and pulmonary metastases Am J Surg Pathol 1991;15:1083-1088.[Medline]
- Guinee Jr DG, Thornberry DS, Azumi N, Przygodzki RM, Koss MN, Travis WD. Unique pulmonary presentation of an angiomyolipoma. Analysis of clinical, radiographic, and histopathologic features. Am J Surg Pathol 1995;19:476-480.[Medline]
- Henske EP. Metastasis of benign tumor cells in tuberous sclerosis complex Genes Chromosomes Cancer 2003;38:376-381.[Medline]
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Abstract
Introduction
