Abdominal cystic lymphangioma

The two hamartomas of lymphatic origin that may present as tumors of the mediastinum and retroperitoneum are lymphangioma and lymphangiomyoma. We report an unusual tumor that had features of an intermediate abnormality between lymphangioma and lymphangiomyoma.

CASE REPORT

The patient, a 15-year-old girl, was admitted to the hospital in December 1990 for evaluation of recurrent cough and expectoration since the age of 4 years. A chest roentgenogram in June 1986 showed mediastinal widening with right paracardiac and left parahilar opacities. Results of investigations were normal except for a 50 percent reduction in vital capacity. She underwent an open lung biopsy in July 1986 with a presumptive clinical diagnosis of sarcoidosis. A right thoracotomy was performed and a wedge biopsy specimen was taken from the inferior margin of the right middle lobe. At surgery, reddish cystic swellings were seen at the right hilum that yielded hemorrhagic fluid on aspiration. No biopsy of the hilar tumor was attempted. The lung biopsy specimen showed areas of atelectasis devoid of granulomas, smooth muscle proliferation, or cystic change.

At the time of present hospital admission, she complained of an increase in cough for five months, persistent hemoptysis, two episodes of hematemesis, and class 2 dyspnea on exertion. She was mildly tachypneic and had moderate pallor. Bilaterally adjacent to the midline, the percussion note was impaired with bronchial breath sounds and coarse crepitations.

Investigations revealed the following: hemoglobin, 6.8 g/dl. The peripheral smear and bone marrow aspiration appearance were consistent with iron deficiency anemia. Results of pulmonary function tests were as follows: vital capacity, 1.32 (3.34); [FEV.sub.1] 82 (80); and Dco, 5.36 (21.46). An upper gastrointestinal (GI) endoscopy revealed two large nodular projections from the antrum with overlying venous dilatation. Results of a barium meal follow through and barium enema were normal. The computed tomographic (CT) scan of the chest and abdomen revealed a large, lobulated, nonenhancing, bilateral, posterior mediastinal cystic lesion (attenuation value, 18 Hounsfield units). The lesion encased the mediastinal vessels, pulmonary veins, tracheobronchial tree, esophagus, and extended into the middle and anterior mediastinum (Fig 1 and 2). Bronchiectatic changes secondary to compression and collapse were seen involving the posterior segment of both upper and lower lobes. The same lesion extended inferiorly into the upper part of the abdomen between the posteroinferior surface of the liver and lesser curvature of the stomach. The lesser curvature of the stomach appeared lobular and the lesion reached up to the lesser sac resulting in dilatation of the entire splenoportal venous axis. Results of skeletal survey were normal. The radiologic appearance suggested a diagnosis of lymphangioma.

At exploratory laparotomy, a large bluish cystic tumor was seen adherent between the liver and stomach. There was discharge of clear fluid on excisional biopsy of the tumor. The cut surface of the tumor revealed cystic spaces. Microscopic examination revealed endothelial cell-lined spaces of varying sizes, some of which had lymphocytic aggregates in the wall. Most of the spaces were empty. Red cells were present in an occasional one. In addition, bundles of smooth muscle cells (red on Masson's trichrome) were found in the wall of the lymphatic channels (Fig 3). On extensive evaluation by light microscopy, smooth muscle cells were seen in approximately 30 percent of the area studied.

DISCUSSION

Lymphangiomas are benign hamartomas arising from a maldevelopment of the primitive lymph sacs. They are tumors of infancy and childhood occurring in the neck (75 percent) or axilla (20 percent). Rarely (1 percent) they occur in the mediastinum where they are confined to one compartment, mostly the superior mediastinum. These tumors are treated by complete surgical excision with excellent results, although recurrences may occur with incomplete extirpation.

Extensive lymphangiomatous tumors are usually a component of generalized lymphangiomatosis in which multiple cystic lesions of the skeleton are seen. However, preoperative radiologic evaluation may fail to reveal the bone involvement demonstrated at surgery.[1] The extraosseous tumor masses present as giant lymphangiomas with a prediliction for involvement of the posterior mediastinum and extension into the retroperitoneum. The results of surgery are disappointing with a high rate of incomplete resection, a stormy postoperative course, and an unacceptably high operative mortality.[2]

Lymphangiomyomatosis is an extremely rare disease occurring exclusively in women of reproductive age. It is characterized by tumor masses (which rarely exceed 10 cm in size, called lymphangiomyomas), chylous effusions (pleural and peritoneal), extensive diffuse cystic disease of the lung, and it is frequently complicated by spontaneous pneumothorax. On histologic study, smooth muscle proliferation is seen in relation to lymphatics, blood vessels, and bronchioles. The disease has a progressive course with a grave prognosis, especially in patients with pulmonary lymphangiomyomatosis, who frequently develop respiratory failure as a terminal event.[3] Hormonal manipulation is presently the treatment of choice.[4]

The clinical and radiologic appearance of the tumor in the present case was consistent with the diagnosis of lymphangioma; however, the size and extent of the tumor were remarkable. The extent of the disease favors generalized lymphangiomatosis, but the CT scans and roentgenograms failed to reveal bone involvement making this diagnosis unlikely. The presence of significant amounts of smooth muscle on histologic study is perplexing and unexplained, as lymphangiomas do not show smooth muscle proliferation. A review of the literature revealed three case reports, all in women, with tumors that clinically resembled lymphangiomas but showed significant smooth muscle on histologic study.[5-7] They were classified differently by the authors as lymphangioma, lymphangiomyoma, and hemangiolymphangioma with component of lymphangiomyomatosis, indicating that, as yet, there is no agreement on their nomenclature. Thus, the diagnostic terminology, clinical course, and therapy of such cases remains to be determined.

In the patient described, as the possibility of complete surgical removal was remote and the risk of postoperative morbidity and mortality was high, a conservative approach was opted for. The patient was started on a regimen of tamoxifen (20 mg/day) with the hope that the presence of significant amounts of smooth muscle would render the tumor susceptible to hormonal manipulation. ACKNOWLEDGMENT: The authors wish to thank Dr. S. Datta Gupta from the Department of Pathology for his review of the pathologic findings and Drs. Brajesh Bhatla and Harminder Singh from the Department of Medicine for their assistance in evaluating the case.

REFERENCES

[1] Brown LR, Reiman HM, Rosenow EC III, Gloviczki PM, Diverti MB. Intrathoracic lymphangiomas. Mayo Clin Proc 1986; 61:882-92 [2] Case records of the Massachusetts General Hospital (case 30-1980). N Engl J Med 1980; 303:270-76 [3] Wolf M. Lymphangiomyoma: clinicopathological study and ultrastructural confirmation of its histogenesis. Cancer 1973; 31:988-1007 [4] Eliasson AH, Phillips YY, Tenholder MF. Treatment of lymphangioleiomyomatosis: a meta-analysis. Chest 1989; 96:1352-55 [5] Bhattacharyya AK, Balogh K. Retroperitoneal lymphangioleiomyomatosis: a 36-year benign course in a postmenopausal women. Cancer 1985; 56:1144-46 [6] Case records of the Massachussets General Hospital (case 5 - 1989). N Engl J Med 1989; 320:301-10 [7] Thomas AMK, Leung A, Lynn J. Abdominal cystic lymphangiomatosis: report of a case and review of literature. Br J Radiol 1985; 58:467-69

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