NK cell enteropathy: a case report with 10 years of indolent clinical behaviour

Abstract

Recognition of NK cell enteropathy is important to avoid over-diagnosing this benign condition as an aggressive lymphoma.

Lymph node involvement by enteropathy-like indolent NK-cell proliferation

“…Extension into the submucosa was reported in some cases [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Importantly, there is no marked cellular atypia, no significant mitotic activity, and no angiocentricity, angiodestructive growth or necrosis [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Immunophenotypic features of the reported cases show a very homogeneous profile consistent with mature NK cell, including expression of cytoplasmic CD3, CD7, CD56, and cytotoxic granules-associated molecules in virtually all cases [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16].…”

“…Except for the unusual location within a lymph node, the features of this EBV-negative NK-cell proliferation are very similar to those described in NKCE, of which forty-seven cases have been reported [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The clinical features of these uncommon lymphoid proliferations, which share some features with indolent T-cell LPDs of the GI tract [17,18], are summarized in Table 1.…”

“…Ki-67 proliferation index is typically reported as low or quantified lower than 50%, but in 5/ 26 cases (19%) a higher fraction of cycling cells was reported, up to 90%. EBER ISH was negative in all cases, and no clonal rearrangement of the TR genes was found in any of the cases where clonality was investigated [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16].…”

“…In roughly half of the cases (21/44) the patients had no specific complaints and the lesions were fortuitously discovered by endoscopy performed for check-up or screening [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Conversely, in 23/44 cases various symptoms were recorded, mostly vague or nonspecific abdominal or epigastric pain or discomfort, sometimes diarrhea or weight loss, for which clinical workup and endoscopic investigations eventually led to the diagnosis [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. At endoscopy, the altered mucosa often consists of Hematoxylin and eosin stain; original magnifications × 8, × 50, and × 400, respectively erythematous, flat or polypoid lesions, superficial erosions, or ulcers [1][2][3][4][5][6][7][8][9][10][11][12][13][14]…”

“…Importantly, there is no marked cellular atypia, no significant mitotic activity, and no angiocentricity, angiodestructive growth or necrosis [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Immunophenotypic features of the reported cases show a very homogeneous profile consistent with mature NK cell, including expression of cytoplasmic CD3, CD7, CD56, and cytotoxic granules-associated molecules in virtually all cases [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. CD2 expression is detected in a subset of the cases (68%), a few CD8+ cases have been reported (4/43, 9%) [9,10,12], while CD4, CD5, and TCR isoforms (β or γ chains) are consistently negative.…”