Pancreatic cavernous hemangioma complicated with chronic intracapsular spontaneous hemorrhage: A case report and review of literature

Abstract

BACKGROUND

Pancreatic cavernous hemangioma (pCH) is a rare type of benign vascular tumor. Making the right diagnosis is challenging due to low clinical suspicion and the lack of existing cross-sectional imaging tools to distinguish it from other pancreatic lesions.

CASE SUMMARY

We describe a male patient, age 18, who presented with a pCH. Computed tomography, magnetic resonance imaging, and ultrasound showed cystic space in the tail of the pancreas. A dark spot sign on the T2 weighted image sequence was observed. Clinically, a mucinous cystic neoplasm with hemorrhage was suspected preoperatively by combining imaging, and the operative indication was clear. The patient underwent a distal pancreatic tumor resection under laparoscopic control. Immunohistochemical staining for CD31 and CD34 was positive; D2-40 was positive in interstitial lymphatic vessels and negative in vascular epithelial cells; and calcium-binding protein was negative. The results support the diagnosis of pCH combined with chronic intracapsular spontaneous hemorrhage. No complications or recurrences were observed during the follow-up period.

CONCLUSION

Chronic spontaneous hemorrhage may occur in pCH, which may greatly influence the accuracy of diagnosis using imaging modalities. Surgical resection for uncertain pCH seems reasonable with a good outcome.

Key Words: Pancreatic cavernous hemangioma; Magnetic resonance imaging; Diagnosis; Chronic spontaneous hemorrhage; Case report

Core Tip: Pancreatic cavernous hemangioma (pCH) is a rare type of benign vascular tumor, which is difficulty to correctly diagnose. The imaging features of pCH differ among the different cases. Herein, we present an 18-year-old male patient who was diagnosed with pCH after surgical resection. On the T2-weighted image of the magnetic resonance imaging, a dark spot sign was observed. The sign represented chronic intracapsular hemorrhage and was not reported before. We hope this case can help us gain knowledge about diagnosing pCH accurately.

INTRODUCTION

Pancreatic cavernous hemangioma (pCH) is an extremely uncommon tumor with no acknowledged typical imaging characteristics in the current literature[1]. As a result, modern imaging may not sufficiently define this benign illness because hemangiomas closely resemble frequent pancreatic tumors, especially when the pCH is complicated by other clinical conditions. In this work, we report an 18-year-old male who failed to be correctly diagnosed preoperatively by imaging modalities. For this patient, pCH complicated with chronic intracapsular spontaneous hemorrhage was confirmed by pathological specimens after surgical resection.

CASE PRESENTATION

Chief complaints

An 18-year-old male patient with an abdominal cyst lesion found during a physical examination one year ago was referred to our hospital for reexamination of the tumor, which was enlarged.

History of present illness

There was no abdominal pain, diarrhea, or significant change in body weight during the course of the disease.

History of past illness

The patient did not receive any relevant treatment before hospitalization and had no history of surgery or medication.

Personal and family history

The patient denied any family medical history.

Physical examination

No positive physical examination sign was identified.

Laboratory examinations

Complete blood counts, aspartate aminotransferase, alkaline phosphatase, bilirubin, serum electrolytes, creatinine, urea, glucose, and serum tumor marker levels were all within normal ranges.

Imaging examinations

Trans-abdominal ultrasound (US) revealed a cystic solid mass with clear margins in the left abdomen, and no obvious blood flow signal was observed in color Doppler flow imaging. Moreover, there was no echo zone between the mass and spleen (Figure 1). A computed tomography (CT) scan revealed an irregular mixed density mass in the splenorenal space of the left upper abdomen, with uneven cystic density and punctate calcification in the cyst wall. The tumor enhancement was not obvious on the contrast-enhanced CT (Figure 2). Magnetic resonance imaging (MRI) showed a round T1 and T2 hypersignal mass, which was about 64 mm × 51 mm in size, in the splenorenal space of the left upper abdomen. The multiple quasi-circular lesions with a high T1 weighted image (WI) signal, low T2WI signal, and slightly low signal fat suppression sequence were seen inside the tumor. No obvious enhancement was observed in the lesions; the cyst wall was slightly enhanced; and fine line enhancement was observed in the delayed period of enhanced scanning (Figure 3). Localized fluid signals were seen around the lesion. Notably, the “dark spot” sign was observed on T2WI.

Figure 1 An 18-year-old male with a huge abdominal cyst lesion was diagnosed by trans-abdominal ultrasound. A: Fluid around the tumor; B: The tumor identified by color Doppler.

Figure 2 Computed tomography scan images. A: Plain scan; B: Arterial phase; C: Portal phase; D: Equilibrium phase.

Figure 3 Magnetic resonance imaging scan images. A: T1 weighted image (T1WI) sequence; B: Coronal position of T2WI sequence; C: T2WI sequence; D: Venous phase of contrast-enhanced magnetic resonance imaging.

Literature review

The term “pancreas hemangioma” was used in a literature search on PubMed and Google Scholar, and relevant papers and their references were examined. In total, 23 works on pCH have been published since 1960[1,4-25], including one case of a child[6]. Finally, 22 cases were enrolled for further analysis.

FINAL DIAGNOSIS

Pathological specimen examination revealed a soft, sac-like red mass (Figure 4). The patient’s pathology corresponds to a chronic retraction blood clot and contains hemosiderin. Microscopically, a monolayer of endothelial cells was observed. Immunohistochemical staining for CD31 and CD34 was positive; D2-40 was positive in interstitial lymphatic vessels and negative in vascular epithelial cells; and calcium-binding protein was negative. The results support the diagnosis of a hemangioma (Figure 5).

Figure 4 Gross pathology shows the tumor is sac-like, soft in texture, and located at the tail of the pancreas.

Figure 5 Hematoxylin-eosin staining and immunohistochemical staining of the tumor. A: Hematoxylin-eosin (HE) staining of the tumor showed proliferative vessels in the fibrous adipose tissue, with different lumen sizes and thicknesses (HE 10); B and C: Immunohistochemical staining showed positive for CD 31 and CD 34; D: D2-40 showed positive on interstitial lymphatic vessels and negative on vascular epithelial cells.

TREATMENT

The diagnosis of mucinous cystic neoplasm with chronic bleeding was proposed after the clinical presentations combined with imaging presentations were taken into consideration. The patient was recommended for surgery according to the Fukuoka guidelines[2]. Finally, we performed a distal pancreatic tumor resection under laparoscopic guidance. The tumor was located in the region of the pancreatic tail and spleen hilum, extending upward to the rear of the splenic vein, and connected to the splenic region of the colon and duodenum below with a relatively clear space and no obvious infiltration. The operation was successful, and no surgery-related complications occurred.

OUTCOME AND FOLLOW-UP

After surgery, the patient had one day of observation in the intensive care unit. He was able to tolerate drinking liquids orally on the second day. On the seventh post-operative day, he was allowed to go home. He had no symptoms or signs of a recurrence six months following surgery, according to CT scans and telephone follow-up.

DISCUSSION

Hemangioma is a tumor formed by the proliferation of angioblast cells during the embryo development that can occur anywhere in the body. Pancreatic hemangiomas are rare, making up about 0.1% of pancreatic tumors[3]. pCH, a type of pancreatic hemangioma, is even rarer and still has an unknown pathogenesis[4].

According to the literature review, the age of onset of adult pCH is between 18 and 79 years old, and the ratio of male to female is about 1:3. pCH occurs most frequently in the head of the pancreas, followed by the tail and body; although, some cases have also occurred in the neck of the pancreas. pCHs exhibit no specific symptoms and have been found due to the non-specific abdominal symptoms, including pain, fever, nausea, vomiting, dizziness, and jaundice. Some pCHs were accidentally discovered during physical examination. Notably, one case with massive upper gastrointestinal bleeding was found to be associated with pCH[16].

The conventional imaging modalities used to diagnose pCH are transabdominal US, CT, endoscopic US (EUS), and MRI. In 10 cases, hemangiomas larger than 5 cm were detected by US. Moreover, US and EUS imaging are generally a hyperechoic no blood flow signal or a mild blood flow signal mass. If there is calcification in the lesion, a strong echo can be observed[17]. In contrast to a mucinous cystic tumor, the lack of a fine speckled internal echo pattern may indicate a vascular tumor[12]. However, in our case, the imaging feature was not present, and no Doppler signal was detected. Poor Doppler signals may be caused by hemorrhage, thrombosis, necrosis, shunting, and the vascularity of the solid component of most pancreatic hemangiomas.

It is pertinent to mention the usefulness of EUS in diagnosing pancreatic lesions. EUS is rarely performed in teenage patients, and the imaging features of EUS may be similar to that of US. Fine needle aspiration may not be applicable in pCH cases due to the risk of bleeding. Moreover, only one study reported the use of EUS in diagnosing pCH[9]. Therefore, the feature of EUS cannot be summarized, and the role of EUS should be explored in future studies.

According to the CT imaging findings of hepatic cavernous hemangiomas, the tumors are generally circular with smooth edges, strong peripheral enhancement in the arterial phase of enhanced scanning, and gradual filling of the contrast medium in the delayed scanning[26]. However, preoperative diagnosis of pCH was proposed in one study based on these characteristics. Hemangiomas cannot be ruled out by a three-phase contrast CT scan that is not enhanced, which was the case in our report. The reason remains unclear, and thus, we should not heavily rely on CT imaging to diagnose pCHs.

Hemangiomas on MRIs show up as a lobulated, hypointense mass on T1WIs and as a moderately hyperintense signal on T2WI[27,28]. Only three studies reported MRI findings: Low T1W signal attenuation was observed in two cases[10,12], and high T2W signal attenuation was observed in another two cases[10,11]. The imaging feature was similar to ours[10,11]. Moreover, the “dark spot” sign was observed on the T2WI sequence. The dark spot sign is an extremely low signal on the T2WIs of cystic lesions, which is specific for chronic hemorrhagic disease and can be seen in hemorrhagic tumors[29]. This article is the first to describe the T2 black spot sign in pCH, which could be attributed to the chronic retraction clots that shorten the T2 relaxation time and the features identified by pathological analysis.

Due to the small number of cases of pCH without special clinical manifestations and atypical imaging features, it is easy to preoperatively misdiagnose. In the majority of cases, surgery was performed without a confirmed diagnosis. pCHs provide imaging features that are similar to the radiographic phenotypes of other frequent pancreatic lesions. It should also be distinguished from pancreatic cystic lesions[30], pancreatic neuroendocrine tumors[31], paraganglioma[32] and pancreatic cancer. We can judge benign and malignant tumors through a combination of clinical manifestations, imaging examination, laboratory tumor markers, and fine needle aspiration.

It is crucial to obtain an accurate histological diagnosis of a hemangioma since other vascular tumors can require a greater surgical margin during resection, adjuvant medication, or a more intensive post-resection follow-up. One study reported recurrence rates of 10%-27% and 50%-100% after total and partial resection in hemolymphangioma, respectively[33]. Hemangiomas consist of an increased number of ectatic capillaries that are filled with blood, have flat endothelium lining them, and are divided by sparse fibrous connective tissue stroma. Vascular spaces may be of the capillary or cavernous kind, depending on their size. Hemangioma, lymphangioma, and other benign vascular tumors are indicated by the presence of vascular endothelial markers (CD31, CD34, and factor VIII-related antigen) coupled with negative cytokeratin (AE1/AE3, D2-40, CAM 5.2, and MNF 116) immunohistochemical staining findings.

Hemangiomas in childhood cannot be treated with tumor resection because they can resolve spontaneously. However, the natural history of adult pCHs remains unclear as they do not present any malignant potential and seem to develop quite slowly. If a certain diagnosis is established prior to surgery, a conservative strategy might be taken into account. For large hemangiomas with persistent diagnostic ambiguity, uncontrolled symptoms after ineffective conservative therapy, or problems resulting from mass impact, surgical excision seems to be a suitable course of action. Successful outcomes were achieved for all patients who had pCHs removed. Similarly, no recurrence was observed in our case after follow-up for 6 mo.

CONCLUSION

In this study, we present a misdiagnosed adult pCH patient case who underwent surgical resection. We propose a novel imaging feature that may aid the correct diagnosis of pCH. The review of literature may constantly help to improve our understanding of this disease and to summarize its clinical and imaging characteristics. As a result, the precise treatment may be achieved.