Ann Thorac Surg 2002;73:1947-1948
© 2002 The Society of Thoracic Surgeons
Case report
Graft-versus-host disease-type colitis: an unusual association of malignant thymoma
Chady Sader, MBBSa*,
Sanjay Sharma, MBBSa,
Mark G. Edwards, FRACSa
a Department of Cardiothoracic Surgery, Royal Perth Hospital, Perth, Western Australia, Australia
Accepted for publication November 1, 2001.
* Address reprint requests to Dr Sader, PO Box 1163, Canning Bridge, Applecross, Western Australia 6153, Australia
e-mail: chady.sader{at}health.wa.gov.au
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Abstract
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We present the case of a patient with a malignant thymoma associated with a graft-versus-host disease-type colitis, of which there has only been a solitary case report in the world literature. Complete surgical resection of the thymoma was achieved; however, the gastrointestinal symptoms persisted.
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Introduction
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Few tumors are associated with as many paraneoplastic manifestations and broad microscopic appearances as thymomas [1]. Graft-versus-host disease (GVHD) is an immunologic process that is most commonly seen after bone marrow transplantation, with the distinctive pathologic finding being apoptosis, a distinctive form of cell death.
A 46-year-old patient presented a 3-month history of severe chronic diarrhea and significant weight loss. His medical history was unremarkable. In particular, no history of prior blood transfusions or immunodeficiency was noted. Multiple investigations were performed, including numerous colonic biopsies, which displayed a lymphocytic colitis with numerous apoptotic bodies within the glandular epithelium suggestive of a GVHD like colitis. A routine chest roentgenogram displayed an anterior mediastinal mass that was subsequently biopsied under computer tomographic guidance (Fig 1)
and revealed a malignant thymoma.
A thymectomy was undertaken through a median sternotomy. The thymus was dissected free from the pericardium and was found to be adherent over the right atrium and right atrioventricular groove. As a result, the pericardium was opened and widely excised. The lesion was also noted to be invading a segment of the right lower lobe of his lung, which was subsequently resected. The right phrenic nerve was sacrificed due to tumor invasion. The tumor was completely resected en bloc with the thymic gland, pericardium, the right phrenic nerve, and part of the right lower lobe. The pericardial defect was reconstructed with Gortex graft (W. L. Gore & Associates, Flagstaff, AZ).
Histopathology revealed an invasive, lymphocytic predominant invasive thymoma invading the pleura with minimal early invasion to the lung. The surgical margins were free of tumor involvement.
Despite complete resection of the tumor, the patient persisted to have debilitating diarrhea necessitating the commencement of steroid therapy.
Adjuvant radiotherapy is being planned, as is regular monitoring for tumor recurrence.
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Comment
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Forty percent of patients with thymoma have at least one paraneoplastic syndrome, including myasthenia gravis, pure red cell aplasia, and a wide array of immune-mediated phenomena [2]. Quite often, these manifestations are the presenting symptoms that lead to a diagnosis of thymoma.
With early experience, thymectomy in patients with myasthenia gravis carried a poorer prognosis due mainly to deaths related to myasthenic crisis. However, it is commonly agreed that earlier surgical intervention now carries no difference in survival in myasthenic patients, with some authors even suggesting a survival advantage [3, 4].
Moreover, patients with concomitant paraneoplastic or immune phenomena have been quoted in the literature as conferring a survival (and recurrence) disadvantage despite the relative paucity of clinical studies involving this group of patients [3, 5–7].
Apoptosis is a form of cell death commonly seen in GVHD. However, it may be seen in a number of other conditions, including hormone-induced thymic involution, pathologic organ atrophy, cytotoxic cell injury (such as immune rejection after transfusion of blood products), and viral injury [8]. None of the latter conditions was thought to have contributed to the gastrointestinal process in this particular case, as numerous viral stool cultures were negative and no viral inclusion bodies were identified in multiple intestinal biopsies. Furthermore, the patient was immunocompetent with no prior immune sensitization. Loss of self-tolerance has been proposed as one possible mechanism by which a GVHD-type immune reaction could result in a thymoma from an altered cellular microenvironment [2, 5, 9]. Cortical overproduction of thymocytes and altered medullary junction influence with interdigitating dendritic cells have also been implicated in theories on autoimmune pathogenesis in thymomas [10].
Given the lack of sufficient experience in predicting outcome with such paraneoplastic phenomena in association with thymoma, caution should be employed in assessing symptoms that may be directly related to the paraneoplastic syndrome (eg, recurrence of diarrhea), as it may represent tumor recurrence.
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References
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Abstract
Introduction
