A Rare Case of Adult Pulmonary Myofibromatosis
Shaohua Wang, MD,
Hailong Huang, MD,
Zheng Ruan, MD,
Kangsheng Song, MD
Department of Thoracic Surgery The First Affiliated People’s Hospital Shanghai Jiao Tong University Shanghai, China
Shaohua Wang, MD, Tel: +86-21-63240090, Fax: +86-21-63240825, Email: thoracicsurgeon{at}126.com, No. 85, Wu jin Rd, Shanghai 200080 China.
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ABSTRACT
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Suspicious bilateral lung nodes were detected incidentally in a 49-year-old man who had undergone a homograft kidney transplant 6 years earlier. Two nodules were excised by a video-assisted left minithoracotomy. The morphological and immunohistochemical patterns were compatible with a diagnosis of pulmonary myofibromatosis.
Key Words: Lung Neoplasms • Myofibromatosis
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INTRODUCTION
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Myofibromatosis is a rare disease, and myofibromatosis in an adult with bilateral lung involvement is extremely uncommon. We report a case of myofibromatosis in an adult, which occurred after solid organ transplantation.
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CASE REPORT
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A 49-year-old man was admitted to our hospital with a high fever for 2 days. He had undergone a homograft kidney transplant 6 years earlier and usually used cyclosporine A, mycophenolate and prednisone for maintenance immunosuppression. He had 2 documented episodes of acute rejection. Laboratory tests showed a white blood cell count of 6.6 x 109/L, neutrophils 86.7%, blood urea nitrogen 10.3 mmol · L–1. The serum creatinine level was 178 µmol · L–1. A chest radiograph showed parenchymal and interstitial infiltrates in both lungs, and suspicious multiple nodules in bilateral lower lobes. Ceftriaxone and ganciclovir were empirically prescribed for 7 days. The patient responded with resolution of his fever and clearance of the infiltrates on chest radiography, but the suspicious nodules remained. High-resolution computed tomography of the chest demonstrated multiple well-defined nodules of variable size, ranging from 0.5 to 0.9 cm in bilateral lower pulmonary lobes (Figures 1
and 2). The sputum smear with routine Gram and acid-fast stains, sputum culture, and sputum cytologic examination were negative. Serum tumor-marker levels were within the normal range. The purified protein derivative test was mildly positive. Thus diagnostic antituberculous therapy with isoniazid and rifampin was given for 2 weeks, but the chest nodules did not show any change. The patient was referred to our department, and a video-assisted left minithoracotomy was carried out. Two palpable peripheral nodules were excised from the parenchyma of the lower lobes, with cautery. The postoperative course was uneventful and the patient was discharged on postoperative day 9. High-resolution computed tomography 20 months after the operation showed no evidence of disease recurrence.
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Figure 1. High-resolution computed tomography scan showing one of the well-defined nodules with a size of 0.8 cm, which was peripheral and excised at operation.
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Figure 2. High-resolution computed tomography scan showing one of the well-defined nodules that was more central in the right lower lobes, and less accessible to biopsy.
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The larger nodule was 0.8 cm in size and the smaller one measured 0.6 cm. On the cut surface, the nodules were grayish in color with a firm fibrous appearance. Microscopically, the tumor cells were composed of 2 types. One type was plump myofibroblasts arranged in short fascicles or whorls (Figure 3). These myofibroblasts were spindle-shaped with pale pink cytoplasm and elongated tapering nuclei with a vesicular chromatin pattern and 1 or 2 small nucleoli. There was no significant atypia or pleomorphism. The other type was less well-differentiated rounded or polygonal cells with slightly larger hyperchromatic nuclei. These cells had relatively scant cytoplasm and were arranged around thin-walled irregularly branching "stag-horn" blood vessels. Both cell types were positive for vimentin and smooth muscle actin. Both were focally positive for desmin and negative for CD34, F8, and HMB45. The morphological and immunohistochemical patterns were compatible with a diagnosis of pulmonary myofibromatosis.
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Figure 3. High-power view showing the typical cytological features: on the upper part are less well-differentiated rounded or polygonal cells arranged around characteristic "stag-horn" blood vessels. On the lower part are spindle-shaped myofibroblasts arranged in short fascicles or whorls. Hematoxylin and eosin stain, original magnification x400.
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DISCUSSION
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Myofibroma or myofibromatosis are terms used to denote the solitary or multiple occurrence of benign neoplasms composed of contractile myoid cells arranged around thin-walled branching hemangiopericytoma-like blood vessels that are also recognized as "stag-horn" blood vessels. Immunohistochemistry markers have no role in confirming the diagnosis but can confirm the origin of the tumor cells and contribute to ruling out other spindle-cell tumors. Myofibroma and myofibromatosis form a morphological continuum with myopericytoma and so-called infantile hemangiopericytoma.1 The lesions can occur over an extremely wide range extending from newborns to the elderly. Myofibromatosis is more common in males.
Myofibroma occurs in the cutaneous or subcutaneous tissues, or skeletal muscle, or aponeuroses, whereas myofibromatosis involves both soft tissues and bone, and frequently occurs in the deep soft tissues and at visceral locations including the liver, kidney, pancreas, gastrointestinal tract, lung, heart, and rarely, the central nervous system.2,3 The relative frequency of solitary and multiple forms is unclear, due to the completeness of radiological studies performed, as some deep lesions were not clinically apparent. In this case, we believe that the fever was related to the parenchymal and interstitial pneumonia, not to the tumor itself. The tumor was discovered incidentally by chest radiography.
Some myofibromas regress spontaneously. A minority of solitary lesion may recur, and the recurrence can be cured by local repeat excision.4 However, there is no definite effective therapy for myofibromatosis. The role of surgery is limited to biopsy only. The extent and location of visceral lesions determines the prognosis, with involvement of vital organs leading to cardiopulmonary or gastrointestinal complications, causing death in rare cases.5 Pulmonary involvement appears to be an especially bad prognostic factor. Myofibromatosis is a rare disease, and myofibromatosis with bilateral lung involvement is extremely uncommon. It is known that transplant recipients are susceptible to infections and tumors because of compromised immune function, but it is difficult to say whether the pathogenesis of the disease is associated with immunosuppression therapy, because of its rare incidence.
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REFERENCES
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- Dray MS, McCarthy SW, Palmer AA, Bonar SF, Stalley PD, Marjoniemi V, et al. Myopericytoma: a unifying term for a spectrum of tumours that show overlapping features with myofibroma. A review of 14 cases. J Clin Pathol 2006;59:67–73.[Abstract/Free Full Text]
- Adickes ED, Goodrich P, AuchMoedy J, Bickers G, Bowden B, Koh J, et al. Central nervous system involvement in congenital visceral fibromatosis. Pediatr Pathol 1985;3:329–40.[Medline]
- Salamah MM, Hammoudi SM, Sadi AR. Infantile myofibromatosis. J Pediatr Surg 1988;23:975–7.[Medline]
- Chung EB, Enzinger FM. Infantile myofibromatosis. Cancer 1981;48:1807–18.[Medline]
- Wiswell TE. Infantile myofibromatosis and the use of magnetic resonance imaging. Am J Dis Child 1988; 142:486.[Abstract/Free Full Text]
Asian Cardiovasc Thorac Ann 2009;
17:199-202
© 2009 by SAGE Publications
DOI: 10.1177/0218492309103326
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ABSTRACT
INTRODUCTION
