Abstract： Objective　To retrospectively analyze the investigation and disposal of the COVID-19 outbreak caused by the transmission of the Omicron variant in infected imported cases, and provide basis for COVID-19 outbreak management. Methods　The description epidemiological method was used to describe the COVID-19 outbreak in Sanya City from March 31 to April 15, 2022. The propagation chain was mapped and the experience gained and shortcomings identified in emergency responses were analyzed. Results　The outbreak resulted in 95 reported locally transmitted COVID-19 cases with a incubation period M(P25, P75) of 4 (3, 5) d. In the 95 cases, the proportion of cases detected through close contact screening, centralized isolation, community screening, control area screening, active treatment (examination), and key population screening were 33.68%, 22.11%, 18.95%, 12.63%, 6.32%, 4.21% and 2.11%, respectively. The epidemic spread for 6 generations, causing 5 clusters of outbreaks and 12 cases of cluster disease. The epidemic affected 12 villages/neighborhood committees, 1 bar, 1 hospital, 1 small clinic, 1 farmer's market, 1 large shopping mall and 1 restaurant in 2 districts of Sanya City. The result of gene sequencing was Omicron variant BA.1.1. Through the immediate launch of emergency plans, nucleic acid and antigen testing, controlling close contact between infected persons and close contacts, suspending indoor business sites, central urban control, and temporary suspension, COVID-19 was controlled within 16 days. Conclusions　The transmission chain of this outbreak was clear and was caused by imported cases. Strengthening the management of the pass, doing a good job in information sharing and docking, timely screening for cases, screening, pushing, controlling high-risk groups, and implementing comprehensive control measures, can effectively prevent the spread of the epidemic, providing a reference for the control of epidemic situations in relevant scenarios.

Objective: To analyze clinicopathological features of parapsoriasis. Methods: Clinical and pathological data were collected from 81 patients with parapsoriasis in Department of Dermatology, Peking University First Hospital between January 2016 and May 2018, and analyzed retrospectively. Results: Among the 81 patients with parapsoriasis, 44 were male and 37 were female, with age ranging from 6 to 77 years. Their disease course ranged from 7 days to 30 years, and the median disease course was 12 months. Moreover, 61 (75.3%) patients were aged less than 40 years, and 20 (24.7%) were aged 41 years and older. Of the 81 patients, 16 (19.8%) were diagnosed with small plaque parapsoriasis, 20 (24.7%) with large plaque parapsoriasis, 37 (45.7%) with pityriasis lichenoides chronica, and 8 (9.9%) with pityriasis lichenoides et varioliformis acuta. Additionally, distribution patterns of lesions included diffuse type in 65 cases (80.2%) , central type in 6 cases (7.4%) , and peripheral type in 10 cases (12.3%) . Histopathological examination of skin lesions revealed liquefaction degeneration of basal cells in 69 cases (85.2%) , migration of lymphocytes into the epidermis in 67 cases (82.7%) , focal parakeratosis in 42 cases (51.9%) , keratinocyte necrosis in 29 cases (35.8%) , extravasation of erythrocytes in 23 cases (28.4%) , epidermal spongiosis in 21 cases (25.9%) , and dermal perivascular focal infiltration in 61 cases (75.3%) . Conclusion Parapsoriasis has characteristic clinical and pathological manifestations, and a close combination of clinical manifestations with pathological features is necessary for its accurate diagnosis.

OBJECTIVETo study the clinicopathologic features, immunophenotype and gene rearrangement of primary cutaneous diffuse large B-cell lymphoma, leg type (PCLBCL).

METHODSSeven cases of PCLBCL were enrolled into the study. Clinicopathologic analysis, immunohistochemical staining and gene rearrangement for IgH and Igκ were undertaken in the study.

RESULTSAll the seven cases were male, and the median age was 72 years. Patients usually presented with multiple purple tumors, nodules, papules and infiltrative plaques. Two patients had a history of leg injury before onset, and one had mosquito bites. Histologically, the tumor involved the dermis and subcutis with dense and diffuse infiltrative pattern composing of centroblasts and/or immunoblasts. Immunohistochemical staining showed that seven cases (7/7) expressed CD20, six (6/6) expressed bcl-2, four (4/4) expressed MUM-1, four (4/5) expressed CD79a, four (4/5) expressed PAX-5 and four (4/6) expressed bcl-6, respectively. All cases did not express CD3ε, CD45RO, CD10 and CD30. IgH gene rearranged bands were detected in three (3/6) cases and Igκ was detected in one (1/5) case. Six of the seven cases died and the remaining patient, who was 44-year-old, was alive after 22 months of follow-up.

CONCLUSIONSPCLBCL is rare, predominantly affects elderly male patients. PCLBCL has poor prognosis and high mortality, but younger patients seem to have better prognosis. Some cases had a history of trauma or mosquito bites. The relationship between the history and the onset of PCLBCL needs further evaluation.

Aged ; Aged, 80 and over ; Animals ; Antigens, CD ; analysis ; Culicidae ; Gene Rearrangement ; Humans ; Immunoglobulin Heavy Chains ; genetics ; Immunoglobulin kappa-Chains ; genetics ; Immunophenotyping ; Insect Bites and Stings ; complications ; Leg ; Leg Injuries ; complications ; Lymphoma, Large B-Cell, Diffuse ; genetics ; metabolism ; pathology ; Male ; Middle Aged ; Prognosis ; Proto-Oncogene Proteins c-bcl-6 ; metabolism ; Skin Neoplasms ; genetics ; pathology