Intramedullary, periosteal, and extraskeletal Ewing sarcomas: retrospective study of a series of 126 cases in a reference center.

OBJECTIVE: To evaluate the proportion of extraskeletal, periosteal, and intramedullary Ewing sarcomas among musculoskeletal Ewing sarcomas. MATERIAL AND METHOD: Our single-center retrospective study included patients with musculoskeletal Ewing sarcoma diagnosed between 2005 and 2019 in our pathology center (cases from our adult bone tumor referral center and adult and pediatric cases referred for review). Recurrences, metastases, and visceral Ewing sarcomas were excluded. Intramedullary Ewing sarcomas were defined by involvement of the medullary cavity. Periosteal cases were defined by involvement of the subperiosteal area without extension to the medullary cavity. Extraskeletal cases were defined by the absence of involvement of the bone tissue and the subperiosteal area. RESULTS: Our series included 126 patients with musculoskeletal Ewing sarcoma, including 118 skeletal Ewing sarcomas (93.7%) and 8 extraskeletal Ewing sarcomas (6.3%). Of the 118 skeletal Ewing sarcomas 112 were intramedullary (88.9%) and 6 were periosteal (4.8%). Extraskeletal Ewing sarcomas were more common in women and in patients older than 40 (p < 0.05). DISCUSSION: The 6.3% proportion of extraskeletal Ewing sarcoma is lower than the median of 30% estimated from the literature. This difference could be explained by an overestimation of extraskeletal Ewing sarcomas of the chest wall (Askin tumors), an underestimation of periosteal cases confused with extraskeletal cases, and the presence of "Ewing-like" soft tissue sarcomas in previous series. Because of its prognostic and therapeutic impact, the distinction of morphologic subtypes requires the cooperation of experienced radiologists and pathologists.

[Extra-nodal NK/T-cell lymphoma, nasal-type, revealed by cutaneous and ocular involvement]. / Atteintes cutanée et oculaire révélatrices d'un lymphome T/NK extra-nodal de type nasal.

BACKGROUND: Extra-nodal NK/T-cell lymphoma (ENKTL) is a form of highly malignant non-Hodgkin's lymphoma. There are two types: nasal forms primarily affecting the oropharyngeal sphere and so-called nasal-type extra-nasal forms in which primary skin involvement is the most common feature enabling diagnosis. Herein, we report a case of systemic nasal-type ENKTL (ENKTL-NT) that was diagnosed based on skin involvement associated with ocular involvement. PATIENTS AND METHODS: A 67-year-old female patient, without immunodepression, was admitted to the dermatology department for a worsening inflammatory scaly patch of skin on her right calf. Secondarily, further lesions appeared on her body as well as a generalized macropapular rash and sores. These were associated with fever spikes, as well as ophthalmoplegia and edema, preventing her from opening her right eyelid. Tests for infectious, autoimmune and inflammatory disorders were negative. A cerebro-orbital scan revealed infiltration and contrast enhancement of the right periocular fat without any mass effect or cerebral extension. A positron emission tomography (PET) scan revealed multiple hypermetabolic skin lesions. Histological analyses indicated dermal-hypodermal lymphomatous tumor proliferation, and immunohistochemical analyses revealed lymphocytes expressing NK-cell markers (strong CD56+ expression), cytotoxic markers (granzyme B and TIA-1), and the presence of Epstein Barr virus (EBV) in the tumor cells. The patient was diagnosed with systemic ENKTL-NT. Her condition deteriorated rapidly, with the onset of refractory macrophage activation syndrome leading to death due to multiple organ failure. DISCUSSION: Skin involvement in ENKTL is non-specific and uncommon, which can delay diagnosis. Treatment is based on polychemotherapy comprising L-asparaginase and possibly consolidation therapy with autologous or allogeneic hematopoietic stem cell transplantation. The prognosis of ENKTL-NT is poor due the more aggressive nature of the disease compared with the nasal forms, with frequent visceral involvement and macrophage activation syndrome. Skin involvement seems to be a poor prognostic factor. Although ocular involvement is documented, its association with skin involvement is rare and mainly secondary to nasal forms of ENKTL. This case of an extra-nasal form of ENKTL-NT with systemic involvement illustrates the difficulty of diagnosis and the poor prognosis of this type of lymphoma.