Clinicopathological analysis of 384 cases of poroid neoplasms including 98 cases of apocrine type cases

Abstract

We examined 384 cases of poroid neoplasms. Most cases (n = 279, 72.7%) exhibited the features of only one subtype. One hundred and ninety-eight cases (51.6%) showed only the features of poroma (P), 20 (5.2%) hidroacanthoma simplex (HS), five (1.3%) dermal duct tumor (D) and 56 (14.6%) hidradenoma (HA). Composite tumors of those four subtypes were observed in 105 cases (27.3%). In the trunk and lower extremities, lesions with the features of P were observed at higher rates than other sites. Those of HS and D were more frequently observed in the lower extremities. Those of HA were seen at higher rates in the scalp, face, neck and genitalia. Ninety-eight cases (25.5%) showed decapitation secretion and diagnosed as apocrine type lesion. Apocrine type lesions were frequently observed in the lesions on the genitalia (40.0%), scalp (31.8%) and trunk (31.1%), whereas at lower rates in those on the neck (21.4%) and lower extremities (24.0%). In apocrine type cases, the lesions were located more frequently on the scalp and trunk than non-apocrine type, whereas were less frequent on extremities. The rate of apocrine type lesions in the cases with only one subtype (19.7%) was lower than that of those with composite tumors (41.0%). In the apocrine type (43.9%), composite tumors are more frequent than in the non-apocrine type (21.7%). In D (40.8%) and HA (32.3%), apocrine type lesions were more frequently observed than other subtypes. In conclusion, it should be noted that a quarter of poroid neoplasms are composite tumors and/or show apocrine differentiation.

Topics in histopathology of sweat gland and sebaceous neoplasms

“…reported 151 composite tumors (35.9%) among 421 poroid neoplasms in 2008. They also reported in 2016 that a series of 384 tumors included 198 P (51.6%), 20 HS (5.2%), five D (1.3%), 56 HA (14.6%) and 105 composite tumors (27.3%) . In their more recent study, fewer D and P were detected, but composite tumors were more frequent than in other reports .…”

“…Furthermore, Ito et al . reported that the sex ratio and mean age at resection were similar for apocrine type lesions and non‐apocrine type lesions.…”

“…While those 10 cases may not be their entire experience, apocrine poroid neoplasms were thought to be uncommon. However, the report by Ito et al . in 2016 indicated that apocrine poroid neoplasms were definitely not so rare.…”

“…However, no investigation based on a large case series has examined the proportion of apocrine tumors among all poroid neoplasms apart from the study by Ito et al . in 2016 . They reported that 98 out of 384 tumors (25.5%) exhibited apocrine differentiation.…”

“…There have been only four reports describing the detailed clinicopathological characteristics of poroid neoplasms based on large case series. Battistella et al .…”