Management Of Microcystic Lymphatic Malformation And Primary Study Of Potential Mechanism Of Postoperative Recurrence

BACKGROUND AND OBJECTIVELymphatic malformation (LM)can be classified to three types: macrocystic, microcystic and mixed type, according to the size of the lumen. The lumen of the microcystic type usually refers to less than2cm. The treatment of lymphatic malformation mainly includes sclerotherapy and surgery. Macrocystic LM can achieve excellent results by sclerotherapy. However, microcystic LM responses poor to sclerotherapy. Moreover, the rate of postoperative recurrence is high in microcystic LM, too. Microcystic LM is currently the unsolved type of the vascular malformation. The purpose of this study was to take some innovational methods to treat different subtype of microcystic LM and investigate the pathological and histological mechanism of postoperative recurrence.MATERIAL AND METHODSThis study included44patients diagnosed microcystic LM from February2012to February2014in our center of vascular tumor and vascular anomly, including12cases diagnosed as lymphangioma circumscriptum. According to the lesion types and locations,12cases of lymphangioma circumscriptum was treated by highly selective electro‐coagulation;13cases of soft tissue microcystic LMwas treated by interstitial infiltrated bleomycin injection, the other17cases were treated by surgery.5patients taken surgical treatment happened postoperative recurrence, which need second surgical resection.2cases of diffuse lymphatic malformation was treated with oral sildenafil and oral sirolimus therapy. Patient information, lesion characteristics, imaging examination, treatment and clinical results are detailed recorded for effectiveness and safety evaluation.5specimens of postoperative recurrence cases were performed HE and immunohistochemical staining (D2‐40, Ki‐67).we studied the mechanism of postoperative recurrence by comparing the lymphatic vessel density and the size of the lumen in the two surgical specimens of the same patients and investigated the Ki‐67positive rate of the specimens from the second surgery.RESULTS12cases of lymphangioma circumscriptum treated byhighly selective electro‐coagulation treatment, all had a reduction of at least90%,and symptoms were all disappeared. Side effects included mild pain (n=9), proliferative scar (n=1), and ulceration (n=1);13cases of microcystic LM treated with interstitial infiltrated bleomycin injection.4cases had excellent results (30.7%),6cases good (46.2%),3cases fair (23.1%).Efficient rate (reduction>50%) is76.9%.All patients had different degree of swelling after treatment, while one had lower lip mucosal necrosis, which healed spontaneously in one month;2cases of diffuse LM using sildenafil and sirolimus therapy respectively, were not seen obvious effect (reduction<25%).The patient treated with sildenafil had mild shrinking after taking the medicine, and the texture of the lesion become soft. One month after the treatment was stopped the lesion size increased obviously. In the process of taking both medicine, no obvious complications were observed; By comparing the pathology of the first and second surgery specimen, the average lymphatic vessel diameter of the former one was91.4um (46‐166), while the latter was47.82um (28‐78)(P <0.05).The average number of the lymphatic vessels in the former unit area was28(15to39), the latter was44(28‐66)(P>0.05). Ki‐67were all negative in recurrent specimensCONCLUSIONSHighly selective electro‐coagulation is effective and safe in the treatment of lymphangioma circumscriptum. In our study objects, the treatment outcome is exciting, and the complication is acceptable; Interstitial infiltrated bleomycin injection is a safe, effective and innovative technologyfor the microcystic LM treatment; Sildenafil and sirolimus are not effective in reducing the size of asymptomatic diffuse lymphatic malformation; When the pathology of the specimens from the second surgery compared with that from the first operation, lymphatic vessel lumen shows no obvious expansion, instead of being smaller than the previous, and no obvious difference of lymphatic vessel density was found. This suggests that postoperative recurrence is not caused by the residual lymphatic vessels expansion, lymphangiogenesis may play an important role in postoperative recurrence in microcystic LM.