Introduction: Malignant peripheral nerve sheath tumors (MPNST) are rare and aggressive sarcomatous tumors with an overall incidence of 0.001%  derived from Schwann cells or pluripotent cells of the neural crest [2-8]. MPNSTs are typically seen in patients aged 20-50 years, and usually in the setting of neurofibromatosis type 1(NF1) and following radiation therapy . The most common sites are the trunk and extremities followed by the head and neck area [7, 8].
Presentation of the Case: This case reports a 50-year-old man with a previous diagnosis five years ago of a Plexiform Neurofibroma (NF) in the posterior distal third of the right leg and ankle. In this case, we review the most important pathological findings and review the literature by reason of the rarity of this lesion. Actually, the patient is currently on regular follow-up and ongoing disease extension study in another hospital for surgical or oncologic treatment decisions.
Discussion: The majority of MPNSTs are derived from neurofibroma or they arise de novo in normal peripheral nerves [9, 2]. It is important to focus on the correct diagnosis and especially in the differential diagnosis with other tumors that can mimic MPNST, which include desmoplastic and metastatic melanomas, as well as synovial sarcoma and fibrosarcomatous dermatofibrosarcoma protuberans [10, 11]. In this article, we discuss a case of a patient with a previous diagnosis of plexiform neurofibroma that some years later presents as an enlarging painful mass that extends to the ankle, a rare location for these tumors as described on the pathological findings and review in the literature.
Conclusion: MPNSTs are very rare sheath tumors that must be suspected in patients with NF1, especially with a previous diagnosis or another benign lesion, because this is a very aggressive and rapidly growing disease.
Malignant peripheral nerve sheath tumors (MPNST); Neurofibromatosis type 1 (NF1); peripheral nerve; ankle; plexiform neurofibroma (NF); trimethylation at lysine 27 of histone-H3 (H3K27me3).
A 50-year-old man with a previous diagnosis of NF1 and a pathological diagnosis of plexiform neurofibroma (NF) in the right ankle in 2016. He had no co-morbid illness, no relevant surgical history, only the previous partial resection in the ankle, and no family history of neurofibromatosis. He had followed up with the dermatologist until he presented a hot lump for a month in the same area of the previous resection with minimal response to antibiotic treatment. The radiological study showed a 18x13x12 cm mass in the posterior distal third of the right leg and ankle without identifying areas of necrosis. Biopsy was taken for study of this new lesion.
Histologic features showed a tumor composed of monotonous spindle cells arranged in intersecting fascicles. At low power, alternating hyper- and hypocellular areas were focally present with enlarged nuclei and variable degrees of nuclear pleomorphism (Figure 1A, B, C). There were no elements of pre-existent neurofibroma, zonal necrosis, or glomeruloid vascular proliferation but there was a high proliferation activity with more than 10 mitosis/10HPF (Figure 1D). Heterologous rhabdomyosarcoma-like or osteocartilaginous differentiation was not present in this case.
Under Processing (Review Completed)
Received date: NOV 19, 2021
Accepted date: , 2021
Published date: 2021
©2021. Mónica Calle García. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Mónica Calle García (2021) Ankle Malignant Peripheral Nerve Sheath Tumor in a Neurofibromatosis I Patient: A Case Report and Review the Literature. OSP J Health Car Med 3:
Ten Dmitry Olegovich
Hospital Manacor (Islas Baleares), Spain. firstname.lastname@example.org