Castleman Disease With Retroperitoneal Manifestation and Kidney Displacement

Introduction

Unicentric Castleman disease is an asymptomatic, lymphatic disorder that mimics the imaging appearance of benign and malignant diseases. The disease is most often associated with the lungs, where a mediastinal mass displaces the adjacent structures. The occurrence of unicentric Castleman disease in association with kidneys is uncommon. The disorder is treated with complete resection and has a low rate of recurrence.

What Is Castleman Disease?

The condition is underdiagnosed due to its non-specific symptoms. The clinical findings can vary among individuals, and there are no diagnostic tests for disease identification.

• Castleman disease is also called angiofollicular hyperplasia, lymphoid hamartoma, and giant cell nodal hyperplasia.

• Castleman disease can appear as unicentric or multicentric, which are differentiated by several lymph node sites involved in the body.

• The disease development risk is high in immunocompromised individuals. Inflammatory, autoimmune, and viral infections like the human immunodeficiency virus are responsible for disease development.

• The main areas affected by the disease are the mediastinum, neck, and abdomen. Other less common regions are the mesenteric, meninges, muscles, and lungs.

• Few patients show generalized lymphadenopathy.

• Multicentric and plasma types of Castleman disease present with symptoms of fever, anemia, weight loss, joint pains, and rashes.

• Unicentric Castleman disease occurs in children and young adults with female predominance.

• Multicentric Castleman disease is an aggressive form and is more common in the elderly population.

• Other symptoms of liver or spleen enlargement, increased susceptibility to infections, fullness in the belly, and pain in enlarged lymph nodes can occur.

What Is the Histological Classification for Castleman Disease?

• Hyaline vascular type: Unicentric Castleman disease is predominantly hyaline (tissue degeneration into a glass-like substance) vascular type in histologic appearance. This type consists of a prominent multiplication of small blood vessels that appear in follicular (region of maturing B cells) and interfollicular (region of maturing T cell) areas. The microscopic features in this disease include onion ring or lollipop appearance, which are pathologic identifiers. The onion ring appearance is a result of an increase in dendritic cells (antigen-presenting cells in the immune system) compared to lymphocytes (a type of white blood cell). Whereas the lollipop appearance is a result of increased hyalinization of small blood vessels in follicles.

• Plasma cell type: This histologic type is often seen in multicentric Castleman disease. Plasma cells are present around the critical regions of nodes. The microscopic examination reveals a layer of plasma cells present between follicular and interfollicular regions. However, this condition does not reveal prominent perivascular hyalinization.

• Mixed type: This histologic type of Castleman disease has microscopic features of both hyaline vascular and plasma cell types.

• Other types of Castleman’s disease are the following:

  • POEMS (polyradiculoneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell proliferative disorder, and skin changes) -associated, HHV (Kaposi sarcoma-associated herpesvirus) -8-negative multicentric Castleman disease: The condition presents with polyradiculoneuropathy (an immune disorder that is acquired and damages the peripheral nervous system), organomegaly (enlarged organs), endocrinopathy (disease of endocrine glands), monoclonal plasma cell proliferative disorder (neoplasm occurring in bone marrow), and skin changes. The presenting clinical features are unique, and the condition is treated with a target on POEMS.

  • HHV-8- negative or idiopathic multicentric Castleman disease: In this type of disease, there are multiple enlarged lymph nodes, flu-like illness, abnormal blood counts, and dysfunction of vital organs. The patient with this type of disease has tested negative for HHV-8 and HIV (human immunodeficiency virus), which is a diagnostic feature.

  • Multicentric Castleman disease TAFRO (thrombocytopenia -low platelet count, anemia-low level of red blood cell, fever, reticulin fibrosis-increased reticular staining, and organomegaly): In this type of disease, the patient presents thrombocytopenia, anemia, fever, reticulin fibrosis, and organomegaly. The patients have normal immunoglobulin levels and mixed or hyaline vascular histology. However, the other types of Castleman disease exhibit variations in immunoglobulin levels.

What Is Retroperitoneal Castleman Disease?

The disease occurs in the retroperitoneum and is a rare phenomenon. Castleman disease in the retroperitoneum region is asymptomatic due to the mass effect on adjacent organs. The symptoms include:

• Recurring abdominal pain in the lumbar region.

• The pain is intermittent, with a dull ache.

• The pain can be felt for a prolonged duration of 6 months.

• There are no aggravating and relieving factors for the pain.

• There is no history of other systemic complications like abnormal bowel movements, urinary complaints, fever, night sweats, rashes in the body, joint pain, loss of appetite, and weight.

• Some patients experience hematuria and flank pain.

• Abdominal examination reveals a single, firm, non-tender, intra-abdominal, retroperitoneal mass.

• Digital rectal examination and external genitalia are normal.

• In rare instances, the compression of the mass on the renal pelvis or proximal ureter can cause hydronephrosis (excess fluid in the kidney).

How Is Castleman Disease Diagnosed?

The disease can mimic inflammatory and malignant pathology. Therefore, making the diagnosis difficult. Retroperitoneal Castleman disease is radiographically and operatively indistinguishable from malignancy.

• Dense calcification is a common finding of retroperitoneal Castleman disease.

• Computed tomography (CT) and MRI (magnetic resonance imaging) are ineffective in diagnosis and are utilized for surgical planning.

• All the blood investigations are normal.

• Tumor markers like carcinoembryonic antigen, lactate dehydrogenase, and alpha-fetoprotein are within normal limits.

• Ultrasonography of the abdomen reveals a hyperechoic mass in the affected region of the abdomen.

• Contrast-enhanced computed tomography shows well-defined enhancing solid mass.

• Examination with MRI reveals an isointense to hypointense mass along with calcifications.

• Radiographic imaging can help in guided fine needle aspiration biopsy that helps in surgical planning.

• In HHV-8 Multicentric Castleman disease, multiple enlarged mediastinal and hilar lymph nodes of 1 to 3 cm (centimeter) in diameter are seen.

What Are the Treatment Options for Castleman Disease?

1. Unicentric Castleman Disease

• En-bloc surgical resection is the best option for treating the disease. The symptoms of adjacent tissue compressions resolve after surgical resection. Even with partial resection of the mass, recurrence or progression of the disease are uncommon.

• In the symptomatic patient with unresectable mass, the volume is reduced by debulking resection, embolization, or cryoablation (freezing of abnormal tissue with a probe) of feeding vessels.

2. Multicentric Castleman Disease

• Steroids- The medication is recommended in severely ill patients to manage inflammation.

• Chemotherapy with Rituximab, Cyclophosphamide, Doxorubicin, Vincristine, and Prednisolone.

• Interleukin-6 has shown promising results in treating multicentric Castleman disease.

• In HHV-8 multicentric Castleman disease, treatment with Rituximab is highly effective.

• HIV patients undergo antiretroviral therapy with Ganciclovir.

• Radiotherapy.

• Surgery.

3. MCD POEMS

• Stem cell transplant.

• In patients with bone marrow involvement, systemic chemotherapy along with radiation are administered.

After the surgical resection of the mass, patients are advised regular follow-ups every three months up to 2 years.

What Is the Differential Diagnosis for Retroperitoneal Castleman Disease?

• Lipomas.

• Leiomyomas.

• Lymphangiomas.

• Xanthogranulomas.

• Retroperitoneal cysts.

What Is the Prognosis for Retroperitoneal Castleman Disease?

The prognosis is good if the tumor mass is resected early. The patients had a nearly 100 % 5-year survival rate. Unicentric Castleman disease has better survivability than multicentric Castleman disease. Castleman disease increases the patient's risk of developing Kaposi sarcoma or lymphoma.

Conclusion

Castleman disease is one of the diseases occurring in the retroperitoneum. The disease can be identified with clinical examination and biopsy. The mass present in the abdomen is a unicentric type of Castleman disease that resolves with early diagnosis and complete resection.