Presentation
The patient was not known to have any medical illness. He presented with recurrent attacks of vague abdominal pain, often accompanied by nausea, vomiting and fatigue for 5 months. No history of loss of appetite, weight loss or altered bowel habits was observed. No palpable mass was detected on examination.
Patient Data
Computed tomography shows a 4 x 5 cm nearly-rounded, well-defined, solid, mildly heterogeneously enhancing mesenteric mass in the left mid abdomen, showing a few coarse calcific foci within and small eccentric area of fluid component. A mildly enlarged small lymph node was also seen adjacent to this larger mass. No perilesional spiculation was seen. No small bowel involvement or obstruction was noted.
99m-Tc-HYNIC nuclear study
99m-Tc-HYNIC (hydrazynopyridine carboxylic acid) nuclear study shows only mild contrast uptake in the mesenteric mass.
Case Discussion
Three distinct subtypes of Castleman disease have been described in literature, namely
- unicentric Castleman disease (UCD)
- human herpesvirus 8 associated multicentric Castleman disease (HHV-8-associated MCD)
- and idiopathic multicentric Castleman disease (iMCD)
Our case was biopsy proven mixed variety (hyaline and plasma cell) CD. Considering biopsy findings and single mesenteric (nodal) group involvement on imaging, a clinical diagnosis of UCD was made.
UCD affects single lymph node or a region of nodes (localized single set of nodes) while MCD affects multiple lymph nodes in the body.1 Unicentric CD usually affects young population (around 30s) and occurs in either chest or abdomen, with none or only mild symptoms, with common hyaline vascular histology variant. Patients with unicentric CD usually do well once the affected lymph node is removed.2,3 Multicentric form usually affects patients in their 50s and 60s, with a high risk of development in patients who are infected with virus called human herpesvirus 8 (HHV-8), that may also lead to life-threatening infection, organ failure and lymphoma.4
Mild tracer uptake in our case on octreotide scan i.e., uptake less than that of liver, was not conclusive for a neuroendocrine tumor (carcinoid). We used 99m-Tc-HYNIC (hydrazynopyridine carboxylic acid) that is in contrast to 111In-octreotide has a higher imaging quality and leads to a lower radiation absorption in patients. However, diagnosis is difficult to establish on imaging alone and complete surgical excision is usual or standard treatment with excellent prognosis and extremely low recurrence rate.
Unicentric hyaline vascular Castleman disease shows classic pathologic features of hypervascular lymph nodes with hyalinization of vessels, which form concentric arrangements (also called angiofollicular lymph node hyperplasia) while plasma cell variety is less common and occurs most commonly in multicentric disease. Radiotherapy may be considered if surgical excision is not an option.
Presence of localized or solitary non-invasive well-defined lymph node mass showing homogeneous contrast enhancement and reduced tracer uptake on octreotide scan were features that supported this diagnosis in our patient. Carcinoid tumors are common in gastrointestinal tract, displaying neuroendocrine properties, calcification, secondary mesenteric involvement being more common and are usually metastatic.5 Lymphoma usually is progressive, associated with contiguous regional and extranodal involvement as well.6 Radiologists need to consider this rare entity in differential possibilities of mesenteric mass and also must know key radiologic features, and imaging options to direct clinicians towards appropriate management plan.
Acknowledgement: Special thanks to case contribution by Dr. Emad Fouad M Said (Consultant Radiologist, KFMMC, Dhahran), Dr. Lina Abdul Samad (Consultant Nuclear Medicine, KFMMC, Dhahran) and Dr. Saad Mohammed Alsubaie (Consultant Histopathology, KFMMC, Dhahran) for providing imaging, scintigraphy and biopsy findings' respectively.