OBJECTIVETo study the clinicopathologic features, immunohistochemical findings and immunoglobulin heavy chain (IgH) gene rearrangement results of primary pulmonary mucosa-associated lymphoid tissue lymphoma (MALToma) and reactive lymphoid hyperplasia.

METHODSTwenty cases, included 13 cases of pulmonary MALToma and 7 cases of pulmonary lymphoid hyperplasia, encountered during the period from 1989 to 2007, were retrospectively analyzed. The samples were paraffin-embedded and stained with hematoxylin and eosin. Immunohistochemical study and semi-nested polymerase chain reaction for IgH gene rearrangement were performed.

RESULTSThe 13 cases of primary pulmonary MALToma were composed of a spectrum of lymphoid cells, including lymphocyte-like cells, centrocyte-like cells and mononuclear B cells with plasmacytoid differentiation. They often had diffuse or marginal zone growth patterns. Lymphoid follicles with neoplastic colonization were apparent. The lymphoma cells spread along alveolar septa and bronchovascular bundles. Vascular invasion was noted in 9 cases, pleura involvement in 6 cases and nodal involvement in 2 cases. Lymphoepithelial lesions (LEL) were identified in 9 cases of pulmonary MALToma. Immunohistochemically, the lymphocytes in LEL were CD20-positive and CD3-negative. On the other hand, LEL was also present in 2 of the 7 cases of lymphoid hyperplasia studied, with a mixture of CD20-positive B cells and CD3-negative T cells. Eight of the 9 cases of primary pulmonary MALToma were positive for IgH gene rearrangement, while all of the 7 cases of lymphoid hyperplasia were negative.

CONCLUSIONSHistologically, the cell population of primary pulmonary MALToma is similar to that of extranodal MALToma occurring in other organs. LEL, though commonly observed in pulmonary MALToma, are not specific and can also be seen in cases of reactive lymphoid hyperplasia. The immunophenotype of intraepithelial lymphocytes in pulmonary MALToma and reactive lymphoid hyperplasia is different. The presence of a monotonous population of CD20-positive intraepithelial lymphocytes supports a diagnosis of MALToma. IgH gene rearrangement study is also useful in differentiating both entities.

Adult ; Aged ; Diagnosis, Differential ; Female ; Humans ; Immunochemistry ; methods ; Immunophenotyping ; methods ; Lung Neoplasms ; pathology ; Lymphoma, B-Cell ; pathology ; Male ; Middle Aged ; Pseudolymphoma ; pathology ; Young Adult

Objective: Total neoadjuvant therapy has been used to improve tumor responses and prevent distant metastases in patients with locally advanced rectal cancer (LARC). Patients with complete clinical responses (cCR) then have the option of choosing a watch and wait (W&W) strategy and organ preservation. It has recently been shown that hypofractionated radiotherapy has better synergistic effects with PD-1/PD-L1 inhibitors than does conventionally fractionated radiotherapy, increasing the sensitivity of microsatellite stable (MSS) colorectal cancer to immunotherapy. Thus, in this trial we aimed to determine whether total neoadjuvant therapy comprising short-course radiotherapy (SCRT) combined with a PD-1 inhibitor improves the degree of tumor regression in patients with LARC. Methods: TORCH is a prospective, multicenter, randomized, phase II trial (TORCH Registration No. NCT04518280). Patients with LARC (T3-4/N+M0, distance from anus ≤10 cm) are eligible and are randomly assigned to consolidation or induction arms. Those in the consolidation arm receive SCRT (25Gy/5 Fx), followed by six cycles of toripalimab plus capecitabine and oxaliplatin (ToriCAPOX). Those in the induction arm receive two cycles of ToriCAPOX, then undergo SCRT, followed by four cycles of ToriCAPOX. Patients in both groups undergo total mesorectal excision (TME) or can choose a W&W strategy if cCR has been achieved. The primary endpoint is the complete response rate (CR, pathological complete response [pCR] plus continuous cCR for more than 1 year). The secondary endpoints include rates of Grade 3-4 acute adverse effects (AEs) etc. Results: Up to 30 September 2022, 62 patients attending our center were enrolled (Consolidation arm: 34, Induction arm:28). Their median age was 53 (27-69) years. Fifty-nine of them had MSS/pMMR type cancer (95.2%), and only three MSI-H/dMMR. Additionally, 55 patients (88.7%) had Stage III disease. The following important characteristics were distributed as follows: lower location (≤5 cm from anus, 48/62, 77.4%), deeper invasion by primary lesion (cT4 7/62, 11.3%; mesorectal fascia involved 17/62, 27.4%), and high risk of distant metastasis (cN2 26/62, 41.9%; EMVI+ 11/62, 17.7%). All 62 patients completed the SCRT and at least five cycles of ToriCAPOX, 52/62 (83.9%) completing six cycles of ToriCAPOX. Finally, 29 patients achieved cCR (46.8%, 29/62), 18 of whom decided to adopt a W&W strategy. TME was performed on 32 patients. Pathological examination showed 18 had achieved pCR, four TRG 1, and 10 TRG 2-3. The three patients with MSI-H disease all achieved cCR. One of these patients was found to have pCR after surgery whereas the other two adopted a W&W strategy. Thus, the pCR and CR rates were 56.2% (18/32) and 58.1% (36/62), respectively. The TRG 0-1 rate was 68.8% (22/32). The most common non-hematologic AEs were poor appetite (49/60, 81.7%), numbness (49/60, 81.7%), nausea (47/60, 78.3%) and asthenia (43/60, 71.7%); two patients did not complete this survey. The most common hematologic AEs were thrombocytopenia (48/62, 77.4%), anemia (47/62, 75.8%), leukopenia/neutropenia (44/62, 71.0%) and high transaminase (39/62, 62.9%). The main Grade III-IV AE was thrombocytopenia (22/62, 35.5%), with three patients (3/62, 4.8%) having Grade IV thrombocytopenia. No Grade V AEs were noted. Conclusions: SCRT-based total neoadjuvant therapy combined with toripalimab can achieve a surprisingly good CR rate in patients with LARC and thus has the potential to offer new treatment options for organ preservation in patients with MSS and lower-location rectal cancer. Meanwhile, the preliminary findings of a single center show good tolerability, the main Grade III-IV AE being thrombocytopenia. The significant efficacy and long-term prognostic benefit need to be determined by further follow-up.
Humans ; Middle Aged ; Antineoplastic Combined Chemotherapy Protocols/therapeutic use* ; Chemoradiotherapy ; Immune Checkpoint Inhibitors/therapeutic use* ; Neoadjuvant Therapy ; Prospective Studies ; Rectal Neoplasms/pathology* ; Thrombocytopenia/drug therapy* ; Treatment Outcome ; Adult ; Aged