br Discussion According to the World Health Organization WHO
Discussion According to the World Health Organization (WHO) definition, MPNSTs are malignant tumors arising from a peripheral nerve or extraneural soft tissue with nerve sheath differentiation. Approximately 50% of MPNSTs are associated with NF-1 with the remainder occurring sporadically. The incidence of MPNST among patients with NF-1 is approximately 10%. In patients with NF-1, MPNSTs often arise within pre-existing neurofibromas, in particular deep plexiform neurofibromas. Radiation exposure is another risk factor for the development of MPNST. A superficial form of MPNSTs with a cutaneous or subcutaneous origin has been identified, and association with solitary neurofibromas was observed. It has been demonstrated that loss of functional NF1 allele in a Schwann cell may be the initial step in neurofibroma pathogenesis, and subsequent progression from neurofibroma to MPNST is associated with additional molecular alterations. However, several key steps in this process remain poorly understood. The diagnosis of MPNST is sometimes difficult due to the histopathological similarities with other spindle cell sarcomas, such as monophasic synovial sarcoma, leiomyosarcoma, and fibrosarcoma. A combination of gross, histopathological, and immunohistochemical studies can be helpful in making the diagnosis (Table 1). Notably, each of these tumors has multiple different variants with atypical morphological characteristics and staining properties. For MPNSTs, neural markers of S-100, CD56, and protein gene product 9.5 (PGF 9.5) have been considered as sensitive markers. S-100, traditionally regarded as the best marker, was found to be expressed in only 50–90% of the MPNSTs. The tumor that perhaps most closely resembles MPNSTs is synovial sarcoma. Synovial sarcomas may involve methysergide and MPNSTs may show glandular pattern. A history of NF1 and/or a co-existing neurofibroma precursor will aid in the diagnosis of MPNST. The prognosis is poor for the deep counterpart of MPNST and the reported crude 2-year and 5-year survival rates were 57% and 39%, respectively. A recent literature reviewed 13 reported cases of superficial MPNST arising in sporadic neurofibroma that demonstrated six cases with local recurrence and two cases with lung metastases. Within the two distantly-metastatic cases, one died of tumor and the other had no follow-up after the metastases were found. Surgical resection is the mainstay treatment, but there is no available guideline regarding how much the margin should be resected around the tumor.
Introduction Lichen sclerosus (LS) is a chronic inflammatory disorder, with white porcelain-like sclerotic lesions. The etiology of this chronic process is unknown. It mainly affects the genital area in postmenopausal women, but is rarely reported occurring exclusively on the extragenital area. Bullous LS is an unusual form of the disease, with hemorrhagic bulla in the genital and/or extragenital areas. The clinical features and long-term outcomes of patients with extragenital bullous LS have been poorly described. We introduce a case with bullous LS exclusively found in the extragenital area, review similar cases reported in the literature, and discuss the clinical features, pathophysiology, and treatment options in an effort to raise awareness of this rare clinical presentation.
Case report A 74-year-old woman presented with a 4-year history of asymptomatic whitish patches on her abdomen and back. There was no other lesion in the genital area. She came to our clinic because a blister occurred on her back 3 months earlier and did not subside. Her medical and family history was unremarkable. On examination, some sclerotic depigmented or hypopigmented patches were found on her abdomen (Figure 1A). There was a large 6 × 4 cm, ivory-colored sclerotic plaque with a tense bulla present on the lower back (Figure 1B and C). She denied either itching or rubbing the affected areas. Laboratory findings including a complete blood count, urinalysis, and liver function tests were normal. Serologic analysis was notable for a positive antinuclear antibody with a titer of 1:40. Serology for Borrelia was negative. A biopsy specimen showed marked edema in the dermal papillae with bulla formation, atrophic epidermis featured by flattening of the rete ridges, mild orthohyperkeratosis, and homogenization of the collagen in the reticular dermis. Mild perivascular infiltration of lymphocytes was focally seen (Figure 2). Direct immunofluorescence was negative.