Neurofibromatosis Type 1 Presenting As Myxoid Neurofibroma

BackgroundNeurofibroma is a benign neoplasm originating from peripheral nerve.It consists of cells derived from nerve sheath and fibroblasts derived from nerve connective tissue.Neurofibromas can be solitary or multiple.Solitary neurofibroma is rare and can occur in any part of the peripheral nerves.The latter,also known as neurofibromatosis,is a systemic disease with dominant hereditary characteristics and can affect all parts of the body,including peripheral nerves and central nervous system,skin,muscle,skeleton and viscera.The pathological types of neurofibroma include classical,myxoid,cellular,transparent,plexiform,epithelioid,diffuse,Parkini,pigmented and granular cell neurofibromas.Reports in MN in the literature are uncommon.ObjectivesWe sought to document a case of neurofibromatosis type 1(NF 1)manifested as MN,and to review the demographic data,clinical manifestations,pathological findings,treatment options and prognosis of MN.Methods1.A case of NF 1 with MN was described concisely according to medical record guideline.2.Search for Chinese case reports of MN indexed in Chinese databases(CNKI,Wanfang Data,and VIP)(search duration: January 1,1970-April 30,2018).3.Search Pubmed,Science Direct,and Google Academics for cases of MN published in English(search duration: January 1,1970 to April 30,2018).4.Paper inclusion criteria: case report in cutaneous MN;exclusion criteria: literature that does not record the basic information of patients.5.Review the recruited case reports in MN in both Chinese and English,extract data,and analyze statistically the demographic data,clinical manifestations,pathological findings,course of disease,treatment plan,prognosis of all the patients,using SPSS19.0 when necessary.ResultsThe case of NF 1 manifested we recorded has the follow features: The patient was a 19-year-old man,having multiple asymptomatic brown spots and skin tumors since more than six years earlier.No obvious abnormalities were found on systemic physical examination.After pathological examination a diagnosis of NF 1 presenting as MN was rendered.Still no treatments were prescribed after his diagnose was confirmed.We advised the patient to observe the potential changes of the disease.When symptoms of tumor compression presenting or tumors involving important organs such as brain and eye,surgical resection of the tumors could be performed.And Café-au-lait spots and freckles could be treated by laser,if he thought these lesions had a negative impact on his appearance.15 cases of cutaneous MN were found in the literature.The feature of these 15 cases and our case were summarized as follows:(1)Sex ratio: male to female was 7:9;(2)Age: The patient ages at the first visit and at the onset of this condition ranged from from 5 to 72(median: 39)years old,and from 2 to 69(median: 38)years old,respectively;(3)Duration of disease: ranged from one month to 26 years;(4)Location of cutaneous MN: cutaneous MN might be located on face,shoulder,arm,nail and foot.(5)Clinical manifestation: a solitary,round or elliptic,flesh-colored or yellowish nodule 3mm-10 cm in diameter,usually with a well-defined border but occasionally with an ill-defined border.It had a smooth surface,and might have a soft,rubber-like or a hard consistence with no tenderness;(6)Pathology of MN: features of classical neurofibroma with a large amount of matrix mucin deposition.Comparing with other histological subtypes,the cell constituents in the lesion were significantly reduced.Schwann cells,nerve cells and fibroblasts could be seen,and a small number of mast cells could also be observed.(7)Differential diagnosis: Other pathologic subtypes of neurofibroma with mucin deposition,including classical,cellular and plexiform neurofibroma;other tumors with mucinous deposition,such as intramuscular myxoma,mucinous protuberant dermatofibrosarcoma,myxoid liposarcoma,low-grade myxoid sarcoma and mucinous carcinoma;(8)Management: If the patient having no tumor compression symptoms,no treatments are mandatory;Surgical or laser removal may be prescribed if tumor compression symptoms present,or a pathologic examination warranted,or the lesions having cosmetologic implication.(9)Prognosis: MN is a benign tumor and no malignant change was reported up to now.Tumor compression symptoms sometimes may be seen.Conclusions1.MN is uncommon both at home and abroad.Although the onset age of MN ranges from children to the elderly,middle-aged population is most frequently affected.It has a predilection of woman over man.2.Clinical manifestations and pathological examination were the main clues for the diagnosis of MN.3.Usually no treatments are mandatory for this tumor,but surgical or laser removal may be prescribed when necessary.4.MN is a benign lesion and no malignant change has been reported up to date;therefore the prognosis of this tumor is generally good.5.Because of the rarity of MN,it is impossible for a clinician to accumulate experiences in this condition,which is why misdiagnosis happens sometimes.Reviewing the clinical features of MN in this paper will facilitate deepening a clinician’s understanding of MN and improving his/her the clinical skill in the diagnosis and management of this condition.