Castleman's disease

Castleman's Disease

Castleman's disease is characterized by lymph node enlargement. There are two distinct histologic subtypes. Most patients are asymptomatic and under age 30, and a mediastinal or hilar mass is found incidentally on chest radiograph. The pathogenesis is unknown, but a chronic inflammatory process has been suggested by some investigators. Complete surgical excision is the treatment of choice and is generally curative.

Castleman's disease, an unusual condition of unknown etiology, was first described in 1954.[1,2] It has also been called giant lymph node hyperplasia, lymph node hamartoma and angiofollicular mediastinal lymph node hyperplasia. The disease is characterized by lymph node enlargement. Two histologic subtypes with differing clinical features have been demonstrated: the hyaline vascular type (90 percent of cases) and the plasma cell type (10 percent of cases).[3]

Clinical Features

Castleman's disease occurs most often in young, otherwise healthy patients, with 70 percent of cases presenting before age 30. An age range of eight to 66 years has been reported. There is no significant sex predominance.[3,4]

Most patients with the hyaline vascular subtype of Castleman's disease are asymptomatic, with a mass noted incidentally on a chest radiograph. When symptoms occur, they most often relate to compression of the tracheobronchial tree (e.g., recurrent infection, cough, dyspnea). Extrathoracic lesions most often present as a palpable mass.[3]

Patients with the plasma cell subtype are much more likely to have systemic symptoms, which may include anemia, fever, sweats and fatigue. Anemia is usually of the chronic disease type and does not respond to iron. Approximately one-half of patients with the plasma cell subtype have a hematologic abnormality (e.g., anemia, elevated erythrocyte sedimentation rate, hyperglobulinemia, leukocytosis, thrombocytosis).[3]

Approximately 70 percent of the lesions occur in the mediastinal or hilar regions; the interior and superior areas of the mediastinum are most often affected. Lesions have also been reported in the neck, axilla, retroperitoneum and pelvis, and within the lung parenchyma.[3] The differential diagnosis includes lymphoma, thymoma, metastatic disease, neurogenic tumors, sarcoma, substernal goiter, sarcoidosis and primary lung cancer.

Etiology

While the cause of Castleman's disease remains unknown, the two predominant theories propose either a chronic inflammatory process or a hamartomatous lesion. Proponents of the inflammatory process theory cite the presence of normal nodal tissue at the periphery of many lesions, suggesting inflammatory transformation of a previously normal lymph node. Some of the histologic features of Castleman's disease resemble those of inflammatory adenitis, and systemic signs and symptoms are consistent with an inflammatory process. In several cases, masses have appeared in patients with previously normal chest radiographs.[3] Those who support the hamartoma theory point out that hamartomatous lesions develop in adult patients and that the angiographic appearance of these masses resembles that of vascular hamartomas elsewhere in the body.[5]

Pathology

The hyaline vascular subtype is characterized by a single mass ranging from 1.5 to 16 cm in size. Adjacent lymph nodes may be involved. In the plasma cell subtype, the clinically identified mass more frequently consists of a cluster of discrete lymph nodes.[3]

Microscopically, the disease is characterized by the presence of lymphoid follicles that are widely scattered throughout the mass, rather than confined to the peripheral cortical area as in normal lymph nodes. In the hyaline vascular subtype, the lymphoid follicles are small, and considerable capillary proliferation is seen both within and between the follicles. The capillaries have plump endothelial cells and are encased by collagenous hyaline tissue. The plasma cell subtype differs by having larger follicles, with intervening sheets of plasma cells, and less vascularity.[3]

Radiologic Findings

PLAIN FILMS

Radiologic investigation is most often prompted by the incidental finding of a hilar or mediastinal mass on a chest radiograph. The mass is usually large and well marginated, and it may or may not be lobulated. There are no distinctive plain film findings to distinguish this disease from other hilar or mediastinal processes.[3]

The chest films shown in Figures 1a and 1b are from a 36-year-old woman with Castleman's disease. The fullness in the superior mediastinum is consistent with a mediastinal mass. The cardiac silhouette in this patient is enlarged, with an amorphous contour suggestive of a pericardial effusion. While pleural effusions have been described in patients with Castleman's disease, pericardial effusions have not been previously reported. The presence of a pericardial effusion in this young, otherwise healthy patient is presumably secondary to Castleman's disease.

COMPUTED TOMOGRAPHY

Mediastinal masses resulting from Castleman's disease may demonstrate prompt homogeneous contrast enhancement. The plasma cell subtype is less vascular, and enhancement may be less pronounced. Computed tomographic (CT) scanning excludes fatty or cystic masses from the differential considerations. Other enhancing mediastinal masses may include substernal goiter, leiomyosarcoma, mediastinitis, neurofibrosarcoma, hypervascular metastases (such as melanoma), medullary carcinoma of the thyroid and parathyroid adenoma. Histologically, Castleman's disease is most often confused with either thymoma or lymphoma. CT scans with contrast may be helpful in avoiding this diagnostic pitfall, since thymoma and lymphoma generally do not enhance on CT scans.[4]

Selective CT images corresponding to the chest films in Figures 1a and 1b are shown in Figures 2a and 2b. There is considerable increased mediastinal soft tissue density, consistent with a superior mediastinal mass. The image in Figure 2b confirms the presence of a large pericardial effusion.

ANGIOGRAPHY

The masses in Castleman's disease are vascular, usually demonstrating a dense, homogeneous blush in the capillary phase of arteriography. Hypertrophic feeding vessels may arise from lumbar arteries in the retroperitoneum.[5] Preoperative embolization has been used to reduce intraoperative bleeding, which can be troublesome.[4]

Treatment

Castleman's disease is a benign process with no reports of malignant degeneration. Complete surgical resection is the treatment of choice and is generally curative. The masses in this disease rarely enlarge.[3,4] In several cases, partial resections have been performed to relieve symptoms, with no evidence of progression of disease over long-term follow-up.[3] Recurrence is more likely, however, with subtotal resection.[6]

REFERENCES

[1.] Case records of the Massachusetts General Hospital.

Weekly clinicopathologic exercises, case

40011. N Engl J Med 1954;250:26-30. [2.] Castleman B, Iverson L, Menendex V. Localized

mediastinal lymph-node hyperplasia resembling

thymoma. Cancer 1956;9:822-30. [3.] Keller AR, Hochholzer L, Castleman B. Hyaline-vascular

and plasma-cell types of giant lymph

node hyperplasia of the mediastinum and other

locations. Cancer 1972;29:670-83. [4.] Onik G, Goodman PC. CT of Castleman disease.

AJR 1983;140:691-2. [5.] Tuttle RJ, Shier KJ. Angiography of angiomatous

lymphoid hamartoma (Castleman tumor) and a

suggested pathogenesis. Radiology 1979;130:

311-5. [6.] Olscamp G, Weisbrod G, Sanders D, Delarue

N, Mustard R. Castleman disease: unusual manifestations

of an unusual disorder. Radiology

1980;135:43-8.

PHOTO : FIGURE 1A. Posteroanterior chest radiograph, showing superior mediastinal fullness consistent with a mediastinal mass.

PHOTO : FIGURE 1B. Lateral chest radiograph, demonstrating enlarged cardiac silhouette with a configuration suggestive of pericardial effusion.

PHOTO : FIGURE 2A. CT scan of the chest, just above the level of the carina. Note the increased soft density obscuring the normal mediastinal fat planes, a finding consistent with a mediastinal mass (M).

PHOTO : FIGURE 2B. CT scan of the chest, at the level of the heart (H), confirming the presence of a large pericardial effusion.

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