Vascular proliferations occurring in the lymph nodes, either localised or pan-nodal, may be detected in various conditions including reactive post-capillary venules, vascular transformation of the lymph nodes and rare vasoformative lesions such as Kaposi's sarcoma [3
]. However, with the exception of Kaposi's sarcoma, primary vascular tumours of the lymph nodes are extremely rare.
Only 16 intranodal haemangiomas have been reported to date [1,3
]. The affected lymph nodes were described in several areas including axillary, common iliac, supraclavicular, submental, inguinal, mesocolonic, submandibular, cervical chain and buccal mucosa [2
]. To our knowledge, this is the first reported case of a pancreatic intranodal haemangioma.
The imaging findings of the intranodal haemangioma reported here are of a well-circumscribed enhancing lesion. The differential diagnosis of a hyperenhancing nodular lesion in the head of the pancreas is broad and consists of a neuroendocrine tumour, metastasis (most commonly from renal cell carcinoma) and islet cell tumours. Although adenocarcinomas of the pancreas are the most common primary malignant tumours of the pancreas, they are generally rich in fibrotic tissue and tend to be hypovascular. Another important finding in patients with pancreatic adenocarcinoma is ill-defined borders with early peripancreatic fatty plane infiltration due to a lack of pancreatic serosa. Peripancreatic vascular invasion and pancreatic duct dilatation are also classic findings in this patient group, especially for tumours arising from the pancreatic head and neck, which were all absent in the present case.
Neuroendocrine tumours of the pancreas are not uncommon and the characteristic imaging finding in a benign neuroendocrine tumour is a well-rounded, arterially enhancing focal lesion. In contrast to their benign counterparts, malignant neuroendocrine tumours may be large at the time of the diagnosis and infiltrative, especially when they are hormonally inactive. Therefore, compared with hormonally active benign and malignant neuroendocrine tumours, hormonally inactive ones are, unfortunately, diagnosed at a later stage.
The contrast enhancement pattern is typically arterially enhancing in small neuroendocrine tumours (<3 cm). However, in larger tumours, heterogeneous enhancement with interspersed necrosis is also common. An interesting imaging finding in the present case is the presence of delayed filling of the lesion in the later phases of dynamic imaging, which is a typical finding of haemangiomas in other solid organs. However, given the rarity and the small size of the lesion, a confident diagnosis of an intranodal haemangioma was not considered in this case.
This article presents an extremely rare lymph node abnormality in a 64-year-old female. Although the pathological features of an intranodal haemangioma have been described before [1
], to the best of our knowledge, the demonstration of contrast-enhanced CT and MRI characteristics of this entity have not been discussed before. Although imaging characteristics are highly non-specific, an arterially enhancing lesion with delayed phase contrast filling may be suggestive of an intranodal haemangioma, given the imaging characteristics of haemangiomas elsewhere in the abdomen. However, confident diagnosis is highly unlikely without pathological confirmation. Intra-abdominal haemangioma in the caecal mesocolon has been reported once as an incidental finding following right hemicolectomy [3
From a pathological standpoint, the differentiation of intranodal haemangioma from primary Kaposi's sarcoma of the lymph node is important. However, the typical features of Kaposi's sarcoma, i.e.
extravasated erythrocytes, vascular obstruction and proliferation of atypical spindle cells were absent in the histological analysis of this case [2
]. In addition, supportive immunophenotyping with endothelial-lined vascular channels was consistent with a haemangioma.