Ann Thorac Surg 2009;87:1268-1269. doi:10.1016/j.athoracsur.2008.08.065
© 2009 The Society of Thoracic Surgeons
Case Reports
A Huge Cystic Cellular Schwannoma of the Intercostal Nerve Presenting With Dyspnea
Wei-Chou Chen, MDa,
Yih-Leong Chang, MDb,
Yung-Chie Lee, MD, PhDa,*
a Division of Thoracic Surgery, Department of Surgery, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
b Division of Thoracic Surgery, Department of Pathology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
Accepted for publication August 25, 2008.
* Address correspondence to Dr Lee, Department of Surgery, National Taiwan University Hospital, No. 7, Chung-Shan South Rd, Taipei, Taiwan (Email: yclee{at}ntuh.gov.tw).
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Abstract
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We report a 73-year-old man who presented with dyspnea that was caused by a huge and single cystic cellular schwannoma in the left chest. He underwent radical tumor excision by a thoracotomy. The patient is doing well, without evidence of recurrence, 8 months after surgical resection.
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Introduction
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Cellular schwannoma is an uncommon variant of schwannoma. It is initially misdiagnosed for malignancy in a high percentage of patients because of its hypercellularity and deep location [1]. They seldom display cystic degeneration and most are partly cystic [2–4]. We report a rare case of a huge, cystic cellular schwannoma presenting with dyspnea.
This 73-year-old man complained of increasing dyspnea for 1 year. A left lung tumor was first discovered 4 years earlier when the patient complained of general weakness. He did not seek medical attention until he had progressive dyspnea. Evaluations with chest roentgenogram (Fig 1A) and computed tomography (Fig 1B) showed a huge cystic tumor in the left thoracic cavity. Analysis of an echo-guided needle biopsy specimen revealed a neurogenic tumor. The lung function test showed severe restrictive and obstructive ventilation defect with 0.82 L of forced expiratory volume in 1 second and 1.16 L of forced vital capacity. The patient underwent radical tumor excision through a left posterolateral thoracotomy. An involved third intercostal nerve was noted in the operation.
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Fig 1. (A) Chest radiogram showed a huge left lung tumor. (B) Computed tomographic scan revealed a cystic tumor in the left thoracic cavity with lung compression and mediastinal shifting. (C) On cut surface, the well-encapsulated tumor was cystic, with muddy content.
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Grossly, the tumor measured 17 x 17 x 5 cm and was well encapsulated. The cut surface displayed a tan and thin-wall cystic tumor with muddy content (Fig 1C). Microscopically, it showed a hypercellular tumor composed of fascicles of spindle cells with predominantly Antoni A areas (Fig 2A) and rare mitotic figures. The tumor cells were diffusely and intensely immunoreactive to S-100 protein (Fig 2B). The degenerative tumor cells constructed the thin cystic wall with acellular content. A huge cellular schwannoma with cystic change was diagnosed.
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Fig 2. (A) The tumor was composed of hypercellular spindle cells and lack of Verocay bodies (hematoxylin & eosin stain). (B) The tumor cells displayed diffuse and strong immunoreactivity for S-100 protein.
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Comment
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Since the original description by Woodruff and colleagues in 1981, more than 200 cases of cellular schwannoma have been reported in the English literature [1–5]. Cellular schwannoma accounts for approximately 5% of benign peripheral nerve sheath tumors [4]. Although cellular schwannoma is a well-recognized variant of the schwannoma, the diagnosis is still difficult and it is mistaken for sarcoma in a large number of cases [1, 4–6].
Cellular schwannoma commonly presents as a painless mass and affects soft tissues such as the retroperitoneum and posterior mediastinum, and also bone [3, 5]. The tumors are most often spherical or ovoid, firm or rubbery. Our patient presented with dyspnea caused by the compression of the lung with mediastinal shifting. Like our patient, most tumors are well circumscribed or encapsulated, and an associated nerve has been identified for 17% to 43% of the cases [3, 4].
Microscopically, cellular schwannomas differ from the classic schwannoma by virtue of a cellular Antoni A component and absence of Verocay bodies [2, 3]. Some amounts of Antoni B may also be present, usually not exceeding 10% of the lesion, but this was not seen in our patient. Some nuclear palisading may be present, and necrosis is generally absent. Mitotic activity may be observed but is usually low, up to 4 of 10 high-power fields.
Support of a microscopic diagnosis of cellular schwannoma can be obtained by immunostains. Like classic schwannomas, cellular schwannomas are usually diffusely and strongly reactive to S-100 protein. Cellular schwannoma must be distinguished mainly from well-differentiated malignant peripheral nerve sheath tumor, leiomyosarcoma, fibrosarcoma, melanotic schwannoma, and solitary fibrous tumor. Errors in diagnosis are reported in 21% to 28% of patients [3–5]. Local recurrences have been reported, but no metastasis or tumor-related deaths [3, 4]. So, it is important to recognized cellular schwannoma as a benign tumor to avoid overtreatment.
Cellular schwannomas commonly have hemorrhage but seldom display cystic degeneration [2]. Partly cystic change has been grossly evident in 3 (5%) patients reported by White and colleagues [3] and in 4 patients (6%) of Casadei and colleagues [4]. To the best of our knowledge, only one cystic pelvic cellular schwannoma has been reported, measuring 15.5 cm at its greatest dimension [3]. As with our patient, much tan-brown fluid and muddy content drained from the cystic interior on sectioning. No relationship between larger tumors and cyst formation has been noted in the literature. Nevertheless, the 2 cystic tumors were large and occupied cavities such as the pelvis and thorax.
In summary, the patient reported here had a rare, huge, cystic, thin-wall cellular schwannoma occupying the thoracic cavity that underwent successful surgical treatment.
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References
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- Laforga JB. Cellular schwannoma: report of a case diagnosed intraoperatively with the aid of cytologic imprints Diagn Cytopathol 2003;29:95-100.[Medline]
- Weiss SW, Goldblum JR. Benign tumors of peripheral nerves Enzinger and Weiss's soft tissue tumor. 5th edition. St. Louis, MO: Mosby; 2008862–6.
- White W, Shiu MH, Rosenblum MK, Erlandson RA, Woodruff JM. Cellular schwannoma. A clinicopathologic study of 57 patients in 58 tumors. Cancer 1990;66:1266-1275.[Medline]
- Casadei GP, Scheithauer BW, Hirose T, Manfrini M, Van Houton C, Wood MB. Cellular schwannoma. A clinicopathologic, DNA flow cytometric and proliferation marker study of 70 patients. Cancer 1995;75:1109-1119.[Medline]
- Woodruff JM, Godwin TA, Erlandson RA, Susin M, Martini N. Cellular schwannoma. A variety of schwannoma sometimes mistaken for a malignant tumor. Am J Surg Pathol 1981;5:733-744.[Medline]
- Alberghini M, Zanella L, Bacchini P, Bertoni F. Cellular schwannoma: a benign neoplasm sometimes overdiagnosed as sarcoma Skel Radiol 2001;30:350-353.[Medline]
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Abstract
Introduction
