Surgical Skin Tumors in Neurofibromatosis 1 (NF1) at the Dakar Cancer Institute
Neurofibromatosis type 1 (NF1) or Von Recklinghausen disease is a genetic condition with autosomal dominant transmission . Signs of Von Recklinghausen’s disease are many and skin tumors represent an important part. The majority of these tumors are benign, but what make the severity of NF1 is the large tumors or royal tumors and the high frequency of malignant nerve sheath tumors .
Patients and Methods
We performed a 6 years retrospective study, from July 2009 to December 2015, involving surgical skin manifestations in Neurofibromatosis type 1. We took into account all NF1 patients according to the Bethesda criteria with skin or subcutaneous tumor for which, size, location or malignancy required a surgical treatment.
They were 08 cases of NF1 associated with skin tumors requiring surgical management. We found 6 women for 2 men with a sex ratio of 0.34. The average age was 35.4 years, ranging from 20 years to 58 years. We noted 5 cases (71.4%) of royal tumors and 3 cases of neurofibrosarcoma (37.5%) (Figures 1 and 2). Malignant tumors sat in the armpit in 2 patients and in 1 patient the tumeur was lacated at the left breast (Figure 3). All royal tumors showed swelling gradually increasing in volume as the initial symptom, and 3 have associated pain.
Figure 1. ulcerated neurofibroma
Figure 2. neurofibroma preventing right eye
In one case the lesions were profuse and tumors were ulcerated and prevent his right eye (Figure 4). The biopsies of the lesions helped distinguish the royal tumor malignancies. Surgical resection has been proposed in all cases. Neo adjuvant radiotherapy was performed in a case of neurofibrosarcoma. Surgery consisted of a resection by mastectomy and axillary lymph node dissection for 1 case of neurofibrosarcoma and the dislocation of the shoulder for 2 tumors of the armpit (Figure 5). After an average period of 48 months, there was no local recurrence for benign and malignant tumors and 1 case of neurofibrosarcoma died.
Figure 3. Neurofibrosarcoma of the left breast
Figure 5. surgery for neurofibrosarcoma of right armpit
Neurofibromatosis Type 1 affects 1 in 3000 to 4000 people without predominance of gender, race or origin. The incidence of cutaneous neurofibromas is 95 to 100% . Men and women are affected to the same extent, and the diversity of expression of symptoms is similar for both sexes.  Surgical cases are not evaluated. They represent 1 case per 4,000 patients in the Cancer Institute of Dakar. We note a female predominance and a young age at diagnosis. NF1 affects adults between 20 and 30 years no sex predominance. The nodular lesions are rare in children .
Royal tumors are often plexiform neurofibromas or skin and subcutaneous mixed tumors that infiltrate the surrounding tissues (bone, muscle, organ) and gradually and constantly increasing volume with age . This is usually the discovery of painful swelling, or dysesthesia like electrical discharge, or functional impairment or infection which causes the patient to consult . The preferred locations of these royal tumors are the body, legs, neck, orbitofrontal or temporal region and abdomen . Their treatment is guided by either the functional or aesthetic embarrassment either in principle on the basis of size .
Malignant tumors are the main complication of NF1 in adulthood with a frequency of 5% against 0.001% in the general population [4,8].
These soft tissue sarcomas occur most often in adults between 20 and 50 years, with a significant male predominance [5,9]. Diagnosis and treatment require histological grading . More than 50% of tumors affect the trunk (50%), 30% affect the extremities and 20% the head and neck region . Some locations, such as breast are exceptional in NF1 .
Standard treatment of localized malignant tumors of nervous sheath (MTNS) is surgery before radiotherapy or chemotherapy whose goal is to facilitate the procedure or reduce the risk of recurrence . The wide excision with surgical margins R0 of these tumors appear to have a significant impact on survival and is associated with longer survival than patients whose surgery was R1 or R2 .
The evolution of cutaneous sarcomas is marked in 50-80% of cases with metastasis to the lungs, lymph relay, bones, liver and brain . Prognosis of MTNS in Nf1 is extremely poor with a survival rate at 5 years of 21% patients while it is 42% for those tumors that occur in the general population . The quality of surgical resection margins is the main predictor of local recurrence. This quality is optimized by the systematic adjuvant radiotherapy rather than radiotherapy on demand [11,12]. The location, stage and tumor grade are the main prognostic factors. Peripheral and superficial tumors have better prognosis than axial and deep tumors .
Surgical skin tumors associated with neurofibromatosis type 1 are represented by the royal tumors and the malignant peripheral nerve sheath. This is a young age human affection. The diagnosis is late and treatment is surgical. It is optimized by adjuvant radiation therapy. The prognosis depends on the size, stage, histological grade the location.
Conflict of interest
Source of funding
Written informed consent was obtained from the patients.
Ka conceived this presentation while Diouf and Dem participated in quality control of this manuscript. All authors read and approved the final manuscript.
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