Uncommon presentation of Castleman disease in the duodenum: a case description and computed tomography imaging analysis

Introduction

Castleman disease (CD) was first described by Castleman et al. in 1956 (1). It represents a spectrum of lymphoproliferative disorders of unknown etiology. CD is classified as either unicentric Castleman disease (UCD), which affects a single lymph node region, or multicentric Castleman disease (MCD), which involves multiple lymph node regions. MCD is further subcategorized into human herpesvirus-8 associated MCD, polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes syndrome-associated MCD, or idiopathic MCD.

The presentation of CD can vary significantly; it can present similarly to gastrointestinal stromal tumor (GIST), lymphoma, schwannoma, ectopic pancreas and entities with Kaposi’s sarcoma-associated herpesvirus (KSHV) etiology, such as Kaposi’s sarcoma inflammatory response syndrome (KS-IRIS) and KSHV-associated cytokine inflammatory syndrome, posing diagnostic challenges. The diagnosis of CD is based on clinical, imaging, needle biopsy findings, and sometimes, surgical excision findings, with surgery occasionally serving as both a definitive diagnostic and therapeutic measure. However, imaging tests still play a crucial role in providing valuable information for diagnosis. We report a rare case of UCD localized in the duodenum. We analyzed its imaging features to improve the preoperative accurate diagnosis of CD and provide valuable clues for subsequent treatment.

Case presentation

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for publication of this article and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

A 65-year-old male presented with a loss of appetite, abdominal distension, and episodic upper abdominal pain without radiating symptoms, starting from July 3, 2021. The pain lasted about half an hour each time, and worsened after eating. His symptoms often improved on an empty stomach or after activity. His bowel movements were normal. The patient had experienced a weight loss of 5 kg over two months and could only tolerate a liquid diet. His laboratory tests, including complete blood count, C-reactive protein, erythrocyte sedimentation rate, creatinine, lactate dehydrogenase, carcinoembryonic antigen, and carbohydrate antigen 19-9, were unremarkable. He tested negative for human immunodeficiency virus.

Computed tomography (CT) scans of the neck, thorax, abdomen and pelvis were performed, and no other lesions were found than those in the duodenum. CT imaging of the abdomen (Figure 1A-1C) revealed a homogeneously dense soft tissue mass located between the right kidney and duodenum, measuring 3.5 cm by 3.7 cm by 6.7 cm, with non-contrast CT attenuation of approximately 42 Hounsfield units (HU). The mass, which was supplied by branches of the celiac trunk, showed significant and uniform enhancement post-contrast, with small, more intensely enhanced nodular and speckled areas at the periphery. The arterial phase CT attenuation of the mass was approximately 96 HU, while the venous phase CT attenuation was approximately 118 HU. The mass exerted compression on the duodenum and the hepatic flexure, but exhibited clear demarcation from surrounding tissues. No significantly enlarged lymph nodes were observed in the retroperitoneum. A preoperative diagnosis of stromal tumor was considered.

Figure 1 A CT scan showed a homogeneously dense soft tissue mass located between the right kidney and duodenum, which showed significant and uniform enhancement (the mass is indicated by black arrows in each panel). (A) Non-contrast CT image. (B) Enhanced CT image of the arterial phase. (C) Enhanced CT image of the venous phase. CT, computed tomography.

Surgical excision of the tumor was performed, followed by histopathological and immunohistochemical analyses. The completely excised tumor appeared as a grayish yellowish white mass, measuring 7 cm by 4 cm by 3.5 cm (Figure 2). The pathological diagnosis was lymphoid tissue proliferation resembling CD, accompanied by granulomas.

Figure 2 The excised tumor appeared as a grayish yellowish white mass, measuring 7 cm by 4 cm by 3.5 cm.

The immunohistochemistry results showed CD3 partial (+), CD5 partial (+), CD20 mostly (+), PAX5 mostly (+), CD21 FDC mesh (+), CD23 FDC mesh (+), CD123 partial (+), CD68 partial (+), CD10 germinal center (+), BCL6 germinal center (+), SOX11 (−), CyclinD1 (−), CD38 partial (+), CD138 partial (+), HHV8 (−), K167 lymphoid tissue 10–80% (+), and granuloma 8% (+).

Discussion

The etiology of CD remains unclear, but it may be associated with autoimmunity, viral infections, and inflammatory factors. Male subjects are slightly more often affected with MCD than female subjects, but for UCD there is no gender preference. The average age of diagnosis for UCD patients is typically younger (fourth decade) than for MCD patients (sixth decade) (2). CD is classified as UCD and MCD, of which UCD is relatively more common (2,3). Based on its pathological characteristics, CD is further classified into hypervascular (HV), plasma cell (PC) and mixed type, of which HV is the most common (2,3). All three pathological types involve blood vessel invasion into the germinal centers, most commonly as HV, characterized by germinal center degeneration and the significant proliferation of follicular dendritic cells (2,4). Cervicothoracic and abdominal lymph node areas are often involved in CD, but involvement of non-lymph node tissue is rare.

Enhanced CT shows significant and homogeneous enhancement of the mass (5,6). PC shows persistent enhancement, and HV shows progressive enhancement. The lesion in this case had clear boundaries, uniform density and uniform enhancement, without any reduction in density during the delayed phase, and showed a rapid wash-in and slow wash-out pattern on the CT scan. This pattern is histologically associated with a large number of capillaries and nutritive vessels in HV-UCD. Small nodular-like enhanced shadows at the edge of the tumor showed persistent enhancement, which were speculated to be related to inflammatory granulation nodules.

In this case, the lesion was located in the duodenum and showed significant enhancement, requiring differentiation from the following diseases on medical imaging (7): (I) GIST: this tumor typically demonstrates moderate to significant enhancement, along with characteristic transmural growth, a “clearance” phenomenon in enhancement, and possible calcification and necrosis, which are common in large tumors. Additionally, coarse vascular shadows may be observed in this tumor; (II) gastrointestinal lymphoma: this lymphoma typically presents as a “sandwich” sign on CT scans and is often accompanied by multiple enlarged lymph nodes; (III) ectopic pancreas: the mass shows uniform density and enhancement pattern identical to that of the pancreas; and (IV) gastrointestinal schwannoma: the tumor shows moderate and uniform enhancement or inhomogeneous progressive enhancement after cystic changes, and often displays extraluminal growth. It is typically <5 cm in size, and may be surrounded by lymph nodes.

Conclusions

The preoperative diagnosis of duodenal CD is quite challenging. A definitive diagnosis of CD sometimes requires surgical resection followed by pathological examination; however, imaging can still provide valuable diagnostic clues. If a lesion appears as a soft tissue mass with uniform density, clear boundaries, significant and uniform enhancement following a rapid wash-in and slow wash-out pattern, and lacks calcification and large vascular shadows, a diagnosis of CD should be considered (8).

Acknowledgments

Funding: None.

Footnote

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-24-704/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for publication of this article and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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