| Abstract|| |
Angiomyomatous hamartoma (AMH) is a rare disease with predisposition for inguinal and femoral lymph nodes. Histologically, it is characterized by replacement of lymph nodal parenchyma with irregularly distributed thick walled blood vessels, haphazardly arranged smooth muscle cells, variable amount of fat and fibrous tissue in a sclerotic lymphatic stroma. Few cases have also been reported in popliteal and sub - mandibular location. The exact pathogenesis is still not known. Although this entity is very rare, its recognition is important in discriminating it from other benign and malignant vascular lesions of lymph nodes.
Keywords: Angiomyomatous hamartoma, benign vascular disease, inguinal lymph node
|How to cite this article:|
Arava S, Gahlot GP, Deepak R, Sharma MC, Nath D, Ashok S. Angiomyomatous hamartoma of lymph nodes: Clinicopathological study of 6 cases with review of literature. Indian J Pathol Microbiol 2016;59:206-8
|How to cite this URL:|
Arava S, Gahlot GP, Deepak R, Sharma MC, Nath D, Ashok S. Angiomyomatous hamartoma of lymph nodes: Clinicopathological study of 6 cases with review of literature. Indian J Pathol Microbiol [serial online] 2016 [cited 2019 Dec 16];59:206-8. Available from: http://www.ijpmonline.org/text.asp?2016/59/2/206/182039
| Introduction|| |
Lymph nodes can undergo vascular endothelial cell proliferation in response to a number of stimuli, which usually occurs in conditions such as vascular transformation of sinuses, inflammatory pseudotumor, bacillary angiomatosis and angiosarcoma or hemangioendothelioma.
Angiomyomatous hamartoma (AMH) is a benign vascular disease of lymph nodes with unknown etiology commonly observed in the inguinal and femoral lymph nodes. Few case reports of these lesions in the head and neck area have also been published in the literature. These lesions are one of the rare causes of asymptomatic lymphadenopathy in the middle-aged individuals causing worrisome to the patient and the clinician. Because these lesions are benign, the treatment of choice is complete surgical excision with a good prognosis. A knowledge regarding this entity is necessary to avoid the erroneous clinical diagnosis of lymphomas or any other metastatic malignancies. Here, we report six cases of angiomyomatous hamartoma with clinical details, differential diagnosis and literature review.
| Case Report|| |
Clinical summary of previous 20 cases reported in the literature along with the present six ones are tabulated in [Table 1]. In our case series, patients age range from 19 to 70 years with the median age of 44.5 years. Male to female ratio is 1:1. 5 out of 6 patients presented with asymptomatic, gradually increasing mass in the inguinal region, whereas 1 patient with postoperative history of carcinoma penis presented with mild lymphedema and painful inguinal lymphadenopathy. All these patients underwent complete surgical excision of the mass with variable clinical diagnosis of reactive lymphadenopathy to lymphoma and metastatic carcinoma. The size of the excised lymph nodes varied from 15 mm to 25 mm. On microscopy, all of them showed similar histopathological features [Figure 1] characterized by partial to complete replacement of the lymph nodal parenchyma with proliferation of irregularly distributed thick and thin walled blood vessels, haphazardly arranged smooth muscle cells and variable amount of adipose tissue in a dense fibrocollagenous stroma. These changes were prominent at the hilar region and extended towards the periphery leaving a thin rim of cortical lymphoid tissue. The lymph node capsule was thickened with obliteration of the subcapsular sinuses. Capillary like vessels were more dispersed at the cortex. Smooth muscle cells were splayed haphazardly in the sclerotic stroma whereas thick-walled blood vessels were prominent at the hilus. Smooth muscle component of the blood vessel wall and the stroma showed immunopositivity for smooth muscle-specific actin, but negative for HMB-45. In view of histomorphological and immunophenotypical features, the diagnosis of angiomyomatous hamartoma was considered. 3 out of 6 patients were followed for 6 months to 24 months with uneventful history, whereas no data of follow-up was available for other 3 cases.
|Table 1: Clinical characteristics of all the 26 cases including the present 6 ones|
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|Figure 1: (a) Lymph nodal parenchyma is replaced by fibrous tissue, numerous thick walled blood vessels with normal cortex at the periphery (b) shows angiomatous and fat component (c) smooth muscle cells are negative for HMB-45 (d) haphazardly arranged smooth muscle cells are immunopositive for smooth muscle actin|
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| Discussion|| |
Hamartoma is an excessive, but focal overgrowth of cells and tissues native to the organ in which it occurs, and it was first coined by Albrecht in 1904. The cellular elements included are usually mature and identical to those found in the remainder of the organ. Hamartomas can be thought of as the linkage between malformations and neoplasms.
Angiomyomatous hamartoma was first defined by Chan et al. in 1992, in an analysis of primary vascular tumors of lymph nodes other than Kaposi sarcoma. It occurs most commonly in inguinal lymph nodes in middle-aged patients., Until now, only 20 cases have been reported in the literature with this being the second largest case series [Table 1].
Although clinicians have varying range of differential diagnosis from reactive lymphadenopathy to lymphoma and metastatic carcinoma, histopathology is the only way for a definitive diagnosis. Microscopically these lesions show complete or partial replacement of the lymph nodal parenchyma with proliferation of the blood vessels, smooth muscle cells and connective tissue stroma. These changes start from the hilum and extends towards the periphery; leaving behind a thin rim of cortical lymphoid tissue with few residual atrophic lymphoid follicles.,
Inguinal lymph nodes were found to be the most preferential site of occurrence of AMH and may be attributed to its most frequent location for other mesenchymal tumors. In total 26 cases including the present 6 ones, inguinal lymph nodes were involved in 21, femoral in 2 and one each from popliteal, submandibular and jugular.
Till now exact pathogenesis of these lesions is not known, however, Sakurai et al., in their study have mentioned impairment of lymphatic flow may be a factor related to its pathogenesis. Only 4 of the 20 cases described in the literature have been associated with the lymphedema of the ipsilateral extremity. In our report, only one case with the history of the carcinoma penis had mild lymphedema. Hence, whether the interference of lymph flow is the cause or the effect of AMH is yet to be determined.
Chan et al. thought that its pathogenesis can either be due to acquired etiology or may represent as a reparative reaction against previous nodal inflammation. However in our case only 1 patient of the carcinoma penis had a previous history of surgery (traumatic etiology).
Histologically, angiomyomatous hamartoma should be differentiated from lymphangiomyomatosis, which usually involves intrathoracic and intra-abdominal lymph nodes with smooth muscle cells arranged in bundles and groups around the ectatic vascular structures.
Magro and Grasso further noted frequent presence of adipose tissue suggesting an “angiomyolipomatous hamartoma” may be a more appropriate for such a lesion., In such cases it should be differentiated from lymph node involvement of angiomyolipoma. The smooth muscle cells of angiomyolipoma have a prominent perivascular arrangement and expresses HMB-45. Our cases had an adipose tissue component however, the smooth muscle cells were immunonegative for HMB-45., Other differential includes nodal leiomyomatosis, which is characterized by proliferation of smooth muscle cells but lacks prominent vascular proliferation.,
Recurrences and metastases of angiomyomatous hamartoma have not been reported. However, impaired lymphatic outflow may lead to the development of a secondary lesion after tumor resection.
In summary, angiomyomatous hamartoma is a rare, benign vascular tumor of uncertain etiology primarily found in inguinal lymph nodes. Although rare, this entity should be considered in the differential diagnosis of benign and malignant tumors of the lymph nodes. Diagnosis is based on histological examination. Once the diagnosis has been established, complete excision of the lesion is the treatment of choice.
We acknowledge Dr. Devajit Nath and Dr. Ashok Singh for their contribution in preparing the manuscript.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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Department of Pathology, All India Institute of Medical Sciences, Academic Building, Ansari Nagar, New Delhi - 110 029
Source of Support: None, Conflict of Interest: None