[Clinicopathological features of acantholytic mammary Paget's disease: a report of 28 cases]

Objective: To investigate the clinicopathological features of acantholytic mammary Paget's disease (AMPD). Methods: From January, 2010 to October, 2016, a total of 28 patients were diagnosed as AMPD in the Department of Dermatology, Peking Union Medical College Hospital. The clinical and histopathological data of these patients were analyzed retrospectively. Results: The patients were all female. The mean age of onset was (51±15)years (range, 24 to 78 years). The median course of disease was 10.5 months (range, 3 months to 2 years). All the cases were unilaterally involved. The ratio of left breast involvement to the right breast involvement was 1.55∶1. In histopathological examination, all the cases showed acantholytic pattern. In addition to that, the prototypical pattern accounted for 50.0% (14/28) of all the AMPD cases. The frequencies of other different accompanied histopathological patterns were: 3 (10.7%) upper nest, 2 (7.1%) budding, 1 (3.6%) tall nest, and 1 (3.6%) sheet-like. Hailey-Hailey-disease-like acantholysis was observed in 18 patients (64.3%), whereas pemphigus-vulgaris-like acantholysis was noted in 7 patients (25.0%) and Darier's-disease-like acantholysis in 3 patients (10.7%). About 75.0% (21/28) of the AMPD cases were found to be accompanied with underlying breast cancers. There was no recurrence in 18 of 20 patients who completed treatment and were followed up for over 1 year. Conclusions: AMPD might involve the left breast more frequently. It is mostly associated with the prototypical pattern of mammary Paget's disease. Hailey-Hailey-disease-like acantholysis may be the most frequent subtype of AMPD. Most AMPD cases are associated with underlying breast cancers, but with a low recurrence rate after treatment.

[Clinicopathological study of 56 cases of extramammary Paget's disease with or without acantholysis]

Objective: To identify the clinicopathological features of extramammary Paget's disease(EMPD) and investigate the clinical and histopathological significance of acantholysis in EMPD. Methods: From June, 2010 to October, 2016, a total of 56 patients were diagnosed as EMPD in the Department of Dermatology, Peking Union Medical College Hospital. Clinical and histopathological data were retrieved from these patients' medical records and analyzed respectively. The cases were divided into two subgroups according to the histopathological pattern (with or without acantholysis): the acantholytic EMPD (AEMPD) group and the non-acantholytic EMPD (N-AEMPD) group. The clinicopathological data were compared and statistically analyzed between the two groups. Results: The AEMPD group included 22 cases (39.3%), while the N-AEMPD group included 34 cases (60.7%). The male: female ratio, the age of onset, and the median duration of the disease were 10∶1 vs 10.3∶1, (64±8)vs (64±10)years, and 42(4-240)months vs 48(3-120) months in the AEMPD and N-AEMPD groups, respectively, with no significant difference (all P>0.05). There was no significant difference in the severe dermal inflammation (27.3% vs 17.6%, P=0.600 ) and cytologic anaplasia(13.6% vs17.6%, P=0.979)between the AEMPD and N-AEMPD groups.Adnexal involvement or dermal invasion (72.7%) was significantly more common in cases with AEMPD, compared to cases with N-AEMPD (23.5%, P<0.001). And 17 cases in the AEMPD group (77.3%) were Hailey-Hailey-disease-like subtype. The recurrence rate after surgical management (29 cases) showed no significant difference between the two groups (1/12 vs 4/17, P=0.370). Conclusions: Acantholysis is common in EMPD. It is not associated with sex, the age of onset, and the duration of the disease. Acantholysis may indicate invasive growth of Paget's cells. Its occurrence has no association with severe dermal inflammation or cytologic anaplasia. Hailey-Hailey-disease-like subtype is the most common subtype in AEMPD, requiring careful consideration to avoid misdiagnosis. Postoperative recurrence is not associated with acantholysis in EMPD.