番茄社区

Why did a 43-year-old man develop a soft, slowly expanding egg-sized lump on his nose? The patient came to the hospital after developing a high fever and nose bleed, and said that the lump had developed about 6 months previously, reported Xiaowen Wang, MD, of Peking University First Hospital in Beijing, and colleagues in .

On taking a detailed history, clinicians learned that he had lost 10 kg since the bump emerged. He did not have any medical disease and denied being a cocaine user. They performed a physical, noting that the skin was reddened along the edges of the mass, which was oozing pus and covered with numerous erosions and ulcers.

Lab tests showed that the patient had moderately low iron levels and high C-reactive protein levels.

A microscopic examination and culture to assess for a fungal infection returned negative results. However, "metagenomic next-generation sequencing of the lesion showed significant positivity for Pseudomonas aeruginosa and Epstein-Barr virus (EBV)," Wang and co-authors wrote. A CT scan of the patient's paranasal sinus revealed mucosal thickening, but otherwise findings were normal. The team obtained skin biopsies and sent tissue samples for histopathological analysis.

Results of laboratory analyses identified the presence of a polymorphous infiltrate within the full thickness of the dermis, made up of a mixture of typical small lymphocytes and atypical lymphoid cells that varied in size. The wall of the blood vessel showed signs of angiodestruction and fibrinoid changes.

Immunohistochemical staining showed elevated expression of CD2, CD56, and cytoplasmic CD3ε in atypical cells. "In addition, in situ hybridization revealed positivity for EBV-encoded small nuclear RNA in the dermis," the authors reported.

The clinical presentation, histological features, and laboratory findings helped to confirm a diagnosis of extranodal natural killer (NK)/T-cell lymphoma, nasal type (ENKL-NT). The patient received radiation treatment, but ultimately died with severe cachexia.

Discussion

ENKL-NT is a malignant EBV-associated lymphoma noted for its tendency to progress rapidly and poor prognosis, Wang and colleagues explained. It occurs more commonly in Asia and Latin America compared with other geographic regions. Clinically, it generally presents as a necrotizing mass affecting the nose, sinuses, or palate, along with local symptoms such as nasal obstruction and epistaxis. As in this case, it is frequently accompanied by fever and weight loss.

Histologically, ENKL-NT tends to be of local angioinvasion and angiodestruction, followed by the gradual progression to necrotic ulceration. The neoplastic cells are intermediate to large in size and display positivity for the surface markers CD2 and CD56, as well as for the cytoplasmic expression of CD3ε. However, these cells lack surface expression of CD3.

The diagnosis of ENKL-NT may be challenging clinically due to its similarity to other midline destructive lesions. Primary differential diagnoses include rhino-orbital-cerebral mucormycosis, granulomatosis with polyangiitis, and lymphomatoid granulomatosis (LYG).

The most common of those, rhino-orbital-cerebral mucormycosis, tends to be seen in patients who are immunocompromised or have diabetes. Characteristically, rhino-orbital-cerebral mucormycosis is by ulceration overlaid with black eschar on the midfacial region, swelling around the eyes, and sinusitis.

A presumptive diagnosis can be made based on pathological evidence of the characteristic hyphae, which should prompt further investigation. Widespread infiltration of normal lymphocytes and other inflammatory cells are also commonly observed, the authors said.

Granulomatosis with polyangiitis is a necrotizing vasculitis that causes a range of symptoms in addition to destructive lesions on the face. Because the condition affects the respiratory tract and kidneys, additional symptoms include coughing, bloody sputum, shortness of breath, and kidney insufficiency. Histological evaluation typically reveals noncaseating granulomas and leukocytoclastic vasculitis.

LYG, which presents with similar to those of ENKL-NT, is another EBV-positive tumor that may appear at extranodal sites, Wang and colleagues explained. However, LYG can be distinguished by the characteristics of the EBV-positive tumor cells, which "originate from B cells and therefore express pan-B-cell markers, such as CD20, instead of markers typical of NK or T cells," they wrote.

Wang and co-authors noted that a standard treatment for ENKL-NT has not yet been identified. Current approaches for patients with localized ENKL-NT include first-line radiation therapy with concurrent or sequential chemotherapy combinations, which they noted "may be more effective than single-agent regimens." that includes L-asparaginase is an essential component of treatments recommended for advanced ENKL-NT.

Presentation of non-nasal-type disease, distant lymph node involvement, advanced disease, and age older than 60 years are significantly associated with a poor prognosis.

"Early diagnosis and treatment of ENKL-NT can improve overall survival, prevent disfiguration, and improve patient quality of life," Wang and colleagues concluded.

Comment