ADULT KAPOSIFORM HEMANGIOENDOTHELIOMA OF THE LEG COMPLICATED BY KASABAKH MERITT PHENOMENON.

Yassamina Ribag, Lahcen Khalfi, Kamal Fiqhi, Adil Ouardi, Issam MokfiI and Karim Elkhatib. Departement of stomatology and plastic surgery. Mohamed V teaching Armed Forced Hospital. Rabat. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History Received: 15 May 2019 Final Accepted: 17 June 2019 Published: July 2019


ISSN: 2320-5407
Int. J. Adv. Res. 7 (7), 530-537 531 The lesion was in the middle third of the anterior side of his right leg. It was painless, bleeding on contact and gradually increasing in size.

Standard X-ray of leg bones showed tibial infiltration
An angioTDM of the leg objectified a vascular tumor with cortical hyperostosis of the tibia. The platelet count achieved during this period was 273,000 plqt: mm3.  Then we completed the surgery, by covering the loss of sustance by two flaps and a skin graft.
The patient was followed up for several months without recidivism, then he was lost. One day he presented to the emergency department. It was noted the presence of multiple nodules developed in the previous surgical site. The tumor mass was painless, immobile and sizing 12x6×5cm. The overlying skin was deep red-purple and bleeding spontaneously with ecchymosis over and around the tumor. Laboratory results demonstrated platelet count 24.000/mm3, normocytic normochromic anemia with hemoglobin 6.3 g/dl, hematocrit 26 %l.
Bleeding was not controlled despite compression dressing over the lesion and the transfusion of packed RBCs (04units) and platelet concentrates (10 units). Methylprednisolone was injected intravenously (5 mg/kg) but no further improvement in platelets or hemoglobin was observed.
The case has been discussed in a multidisciplinary setting including hematologist, plastic surgeon and anesthesiologist.

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In the absence of other alternatives, it was decided to perform a transfemoral amputation of the right leg.
Platelet count rapidly had increased to 66.000/mm3 and hemoglobin had improved to 10,3 g/dl, no bleeding of incisional wound was observed.
In the second post-operative day, his report showed platelet count of 115.000/mm3. His follow up was uneventful.

Discussion:-
Kaposiform hemangioendothelioma (KHE) is a rare borderline vascular tumor with locally aggressive behavior. It was first described in 1993 by Zukerberg,and al, it presents common features to both hemangiomas and Kaposi's sarcoma (1,2).
It usually occurs in newborns or infants less than 6 months (3) and rarely in adults.
Cutaneous KHE adopts a characteristic violet color and typically grows in an aggressive infiltrative manner involving the underlying skin, most commonly as a superficial or deep soft tissue mass on the extremities (1, 23) and trunk. (1,15,20).
It is a badly limited lesion, indurated, often hot; it was the case of our patient.
KHE is usually a solitary tumor (1), some cases of multifocal HEK have been recorded (24).
The cellular area of this tumor is mainly composed of infiltrating lobulated nodules with slitlike or crescentic vessels which are poorly canalized and lined by spindle shaped endothelial cells. The tumor partially contains glomeruloid structures and capillary hemangioma-like structures with clear vascular cavities. Immunohistochemical staining for CD34 and proxy 1 are positive. (1,13,15,22,24,25,26).
In our case, the histological exam demonstred the same things: spindle cells with irregular bundle pattern and slit like vascular cavities. Immunohistochemical staining for CD34 was positive.
The value of radiologic imaging, including computed tomography or ultrasonography, in patients with KHE is unclear because of a paucity of reports.
Doppler ultrasounds show the KHE as a badly limited mass with variable echogenicity, vascular density and sometimes presence of calcifications.
Magnetic resonance imaging is the imaging modality of choice in KHE, it helps to evaluate the evolution and tumoral extension (18). The KHE appears like an heterogeneous mass, iso to hypoT1, hyperT2, infiltrating the subcutaneous fat, destructing and remodeling the adjacent bone (1,27,28,29) These results are quite similar to ours.

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Wide surgical excision of KHE seemed to be its radical and definitive treatment according to the literature (2,30), unfortunately, this was not our patient s case. Despite the oncological excision, surgery could not prevent recurrence of the tumor and its progression to KM P.

The evolution of KHE is fast and does not tend to regress spontaneously, if not treated it could evolve to KASABAKH MERITT Phenomenon (3).
Kasabach-Merritt syndrome (KMP) was first noted by Kasabach and Merritt in 1940 when they described a newborn male baby with a rapidly enlarging capillary hemangioma in association with increasing extensive purpura of the skin and thrombocytopenia.
KMS is characterized by a rapidly enlarging vascular anomaly and consumptive coagulopathy with thrombocytopenia, a prolonged prothrombin time, a partial thromboplastin time, hypofibrinogenemia, and the presence of D-dimer and fibrin split products, with or without microangiopathic hemolytic anemia (3,31).
The mechanism for consumption coagulapathy of KMP is thought to be platelet trapping by the tumor, it is due to the interaction between abnormally proliferating endothelium within the hemangioma and the platelets, which leads to the activation of platelets and a secondary activation of coagulation cascades and the consumption of various clotting factors (31).
In practice most KMP occurs before the age of 6 months, it is exceptional in adults.  (14).
The management of KMP must be multidisciplinary including surgeons, anestesist, hematologist... and must have two goals: the control of coagulopathy and the eradication of the vascular tumor. (3) The administration of fresh frozen plasma, packed RBCs and platelets concentrate is indicated in cases of haemorrhage or if a surgical procedure is considered (30).
Surgical excision of the tumor appears to be the most effective treatment of the KMP (1,30,31) Tumor embolization, radiotherapy, laser, cryotherapy, high dose systemic corticosteroids, interferon alpha 2a or 2b, vincristine, antiplatelet agents, antifibrinolytics, and propanolol are all treatments that can be proposed in the PKM, indicated alone or associated, depending on the doctor's habits and on the treatment availability. (32,33,34,35) More recent and promising treatment is sirolimus (36). Sirolimus has been described to decrease tumor burden and to cause cell apoptosis.
Because of the imminently life-threatening tumor, we estimated that the time to respond to these medical therapies is considered too long and consequently they were not an option. In addition, the effectiveness of these treatments has been inconsistent and currently, there are no known treatment guidelines.
Transarterial embolization is an effective therapeutic option specially in case of unresectable tumor due to its large size and infiltrating nature (31).
Unfortunately, this option was not available in our hospital at the time of admission.

Conclusion:-
KMP is a very rare tumor in adults, only one case was found on literature. There are no guidelines of its treatement. Howeever, surgery seems to be the most effective.