Indian Dermatology Online Journal

LETTER TO THE EDITOR
Year
: 2015  |  Volume : 6  |  Issue : 3  |  Page : 225--226

Malignant peripheral nerve sheath tumour in a patient with a plexiform neurofibromatosis


Ravi Nekkanti, Raghunath Prabhu, Annappa Kudva, Sakshi Sadhu 
 Department of Surgery, Kasturba Medical College, Manipal University, Manipal, Karnataka, India

Correspondence Address:
Dr. Raghunath Prabhu
Department of Surgery, Kasturba Medical College, Manipal University, Manipal - 576 104
India




How to cite this article:
Nekkanti R, Prabhu R, Kudva A, Sadhu S. Malignant peripheral nerve sheath tumour in a patient with a plexiform neurofibromatosis.Indian Dermatol Online J 2015;6:225-226


How to cite this URL:
Nekkanti R, Prabhu R, Kudva A, Sadhu S. Malignant peripheral nerve sheath tumour in a patient with a plexiform neurofibromatosis. Indian Dermatol Online J [serial online] 2015 [cited 2020 May 27 ];6:225-226
Available from: http://www.idoj.in/text.asp?2015/6/3/225/156431


Full Text

Sir,

Malignant Peripheral Nerve Sheath Tumors (MPNST) occur most often among patients with plexiform neurofibroma (NF)-1 and should be suspected in patients who complain of a sudden increase in size or pain following a latent period of 10 years or more.

We present a case of a 21-year-old man with a history of gradually increasing swelling in the lower back for the past 14 years. In the last 2 years, he noticed a rapid increase in size of the swelling and was associated pain. In addition, multiple café au lait macules along with several discrete cutaneous NFs were present over the chest and anterior abdominal wall. A tender, nearly spherical, nonreducible mobile swelling with diffuse borders measuring 15 cm × 13 cm was seen in the midline over the lower back [Figure 1]. Slit lamp examination of the eye revealed iris hamartomas (lisch nodules), favoring a diagnosis of NF 1. Magnetic resonance imaging (MRI) of the back showed a lesion that was iso-intense on T1-weighted and hyper-intense on T2-weighted imaging with intra-lesional areas of hemorrhage; findings consistent with the diagnosis of a PNST. There was no history of neurological deficits, paraesthesias or visual disturbances. Chest X-ray and ultrasound of the abdomen did not reveal any metastasis.{Figure 1}

Patient underwent wide local excision of the tumor. Histopathology revealed a biphasic tumor with hyper-cellular [Figure 2] and hypo-cellular [Figure 3] areas composed of fascicles of spindle-shaped cells. Focal areas of nuclear buckling and entrapped nerves were seen. Periphery of the tumor showed an NF. Findings were suggestive of an MPNST arising in a background of NF. Vimentin was positive in the tumor cells [Figure 4]. S 100 was focally positive in the MPNST and diffusely positive in the NF [Figure 5]. He received adjuvant external beam radiotherapy 50 Gray for six weeks. The patient is symptom free and is on regular three monthly follow-up.{Figure 2}{Figure 3}{Figure 4}{Figure 5}

The incidence of MPNSTs in the general population is only 0.001%, [1] with no gender [1] or race predilection. MPNSTs are estimated to occur in 2-5% of patients with NF-1, and half the cases of MPNST occur in the background of NF-1. [2] Individuals with NF 1 with a plexiform type of NFs are at 18 times higher risk of developing MPNST than those patients who do not have internal plexiform NFs. [3] Malignant transformation of a preexisting NF should be suspected whenever a patient with NF-1 gives history of rapid change in size of tumor or pain, or onset of neurologic deficit. [4] Predisposing factors include tumor size, grade and location at the time of presentation. Mutation in the tumor suppressor gene p53 is associated with an increased chance of malignancy. MRI provides preoperative information about the site and extent of the tumor and rules out distant spread. Intra-tumoral lobulation and the presence of a high signal-intensity area on T1-weighted are considered to be diagnostic indicators of MPNST. The high specificity of flurodeoxyglucose positron emission tomography makes it a better diagnostic modality. [5] To establish malignant changes in a NF, a multiple quadrant open biopsy of the tumor is advocated [6] particularly when an excision biopsy is not possible. Once a diagnosis of MPNST is recognized, the mainstay of treatment is wide excision with oncological clearance to the extent possible. Radiotherapy is currently recommended postoperatively by the oncology consensus group. Local recurrence as high as 32-65% has been reported following wide local excision with tumor free margins after a median interval of 5-32.2 months. [6] Role of chemotherapy with doxorubicin, ifosfamide and etopside is under trial. Recent advances with targeted therapies like histone dieacetylase inhibitors have shown promising results. [7]

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