Ann Thorac Surg 2008;85:1807-1809. doi:10.1016/j.athoracsur.2007.11.037
© 2008 The Society of Thoracic Surgeons
Case Reports
Pediculate Mucinous Cystadenoma Difficult To Differentiate From Pleural Tumor
Hitoshi Igai, MD*,
Norihito Okumura, MD,
Keiji Ohata, MD,
Tomoaki Matsuoka, MD,
Kohtaroh Kameyama, MD,
Tatsuo Nakagawa, MD
Department of General Thoracic Surgery, Kurashiki Central Hospital, Okayama, Japan
Accepted for publication November 14, 2007.
* Address correspondence to Dr Igai, 1-1-1 Miwa, Kurashiki-shi, Okayama, 710-8602, Japan (Email: hitoshi-iga{at}hotmail.co.jp).
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Abstract
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We present a case of benign pediculate mucinous cystadenoma in a 60-year-old man. The tumor, which was connected with the lung parenchyma, was difficult to distinguish from a pleural tumor radiographically. Initially, computed tomographic–guided needle aspiration biopsy was performed to confirm the diagnosis, but this was unsuccessful. Therefore, surgical resection was performed to diagnose and treat the tumor, and pathologic examination of the specimen revealed mucinous cystadenoma. The problems associated with the diagnosis and treatment of pediculate mucinous cystadenoma are discussed in light of this case.
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Introduction
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Although mucinous cystadenomas of the ovary and the appendix have been well described, there have been few reports about mucinous cystadenoma of the lung [1, 2]. Most previous reports have indicated that pulmonary mucinous cystadenoma occurs predominantly in the peripheral region of the lung [3, 4]. Additionally, the typical radiologic features of pulmonary mucinous cystadenoma, which tends to appear as a well-demarcated solitary cystic mass, may be helpful for distinguishing it from other malignant diseases [4]. To our knowledge, there have been no reports of pulmonary mucinous cystadenoma requiring distinction from pleural tumor.
Here we report a case of pediculate mucinous cystadenoma that was difficult to differentiate from pleural tumor radiographically, and review the relevant literature.
A 60-year-old man was admitted to our hospital because of an abnormal shadow that had been detected by chest roentgenography during a routine medical examination. He was asymptomatic at the time of admission.
Initial chest roentgenography revealed lenslike opacity in the upper right thorax (Fig 1). Additionally, chest computed tomography demonstrated a homogeneous D-shaped 60-mm opacity with a smooth margin in the same area (Fig 2). Fifteen years earlier, radiographic examination at another institution had shown a lesion in the same location measuring 4 cm in diameter, and in view of the relative enlargement of the mass shadow, the patient was anxious for the lesion to be definitively diagnosed. Initially, computed tomographic–guided needle aspiration biopsy was performed, but the diagnosis was inconclusive. Therefore, surgical resection was performed using video-assisted thoracic surgery for definitive diagnosis and treatment. A pediculate tumor about 60 mm in diameter was observed, and this was resected using an Endo-GIA Roticulator 60–4.8 SULU (Tyco Healthcare Japan, Tokyo, Japan) at the region of pediculation. The tumor was a multilocular cyst measuring 60 x 40 x 25 mm, and filled with gelatinous mucin (Fig 3). Intraoperative rapid pathologic examination revealed that the tumor was not malignant. Therefore, partial resection was considered to be an adequate treatment. Macroscopically, the surrounding lung parenchyma and visceral and parietal pleura appeared to be normal. Histologic examination showed that the cyst was filled with dense gelatinous mucin. No mitotic figures or cancerous cells were detected (Fig 4). The postoperative course was uneventful, and the patient was discharged on the third postoperative day. Currently there is no evidence of recurrence 3 months after surgical resection.
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Fig 1. Chest radiograph film on admission, showing a lenslike opacity (arrowheads) in the upper area of the right thorax.
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Fig 2. Chest computed tomography demonstrates a homogeneous D-shaped 60-mm opacity with a smooth margin (arrowheads) in the right thorax.
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Fig 3. Macroscopic appearance of the resected mucinous cystadenoma. This cystic tumor was multilocular, and the internal cavity was filled with gelatinous mucin.
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Fig 4. Microscopic appearance of the resected mucinous cystadenoma. The histologic sample revealed a pediculate and multilocular cyst, which was filled with dense gelatinous mucin (arrowheads). No mitotic figures or cancerous cells were detected.
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Comment
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Pulmonary mucinous cystadenoma is an uncommon tumor, generally appearing as unilocular and filled with mucin [5]. As it is benign, the prognosis is good after complete resection [5, 6]. Generally, most cases are asymptomatic and detected by routine medial examination, as was the present case.
Previous reports have described that mucinous cystadenoma appears as a well-demarcated nodular lesion by chest roentgenography and computed tomography, being located in the periphery of the lung parenchyma and varying in diameter from 5 to 7.5 cm [1–6]. In contrast, the radiologic appearance in the present case was a lenslike opacity in the upper area of the right thorax, suggesting that the tumor was located outside the lung parenchyma, although the maximum diameter was 6 cm, and thus similar to those reported previously. This "extrapleural sign" made it difficult to distinguish from a pleural tumor, and we considered that this sign was indicative of a pediculate tumor. We describe a pediculate mucinous cystadenoma difficult to distinguish from a pleural tumor. In this case, surgery was performed under video-assisted thoracic surgery, which is considered to be an appropriate modality for pulmonary mucinous cystadenoma because of its tendency to be located in the lung periphery and its benign nature. Moreover, the pediculation of the tumor allowed it to be resected easily by video-assisted thoracoscopic surgery.
In many cases of mucinous cystadenoma, the diagnosis is confirmed by surgical resection, and this was also the case for the present tumor. Because of the benign nature of the tumor, in many cases partial resection is recommended. In contrast, Matsuo and colleagues [3] suggested that pulmonary lobectomy might be a safer procedure, considering the possibility of recurrence and the size of the tumor. However, although the case reported by Matsuo and colleagues [3] did recur, we consider that partial resection is the best procedure if the surgical resection margin is clear.
The present case of mucinous cystadenoma had demonstrated gradual growth on radiographic images for about 15 years, which made us suspect it might be a slowly growing malignant tumor. Although mucinous cystadenoma is generally benign, it must be distinguished from mucinous cystic adenocarcinoma and mucinous forms of bronchioalveolar cell carcinoma pathologically. Mucinous cystic adenocarcinoma exhibits necrosis and foci of malignant goblet cells, which are definitely absent from mucinous cystadenoma [5]. Also, mucinous forms of bronchioalveolar cell carcinoma lack a cyst wall and show nuclear pleomorphism and lepidic spread of the malignant cells [7]. We considered that secondary mucin production had caused internal growth of the tumor in the present case.
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References
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- Matsuo T, Yusuke Kimura N, Takamori S, Shirouzu K. Recurrent pulmonary mucinous cystadenoma Eur J Cardiothorac Surg 2005;28:176-177.[Medline]
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- Graeme-Cook F, Mark EJ. Pulmonary mucinous cystic tumors of borderline malignancy Hum Pathol 1991;22:185-190.[Medline]
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Abstract
Introduction
