Table 2.

Histological characteristics and regional metastatic status of primary epididymal adenocarcinoma were reported in the literatures from 2007 to 2017.

Ref.	Diagnosis	Tissue Structure	Cell morphology	Nucleus	Cytoplasm	Invasion	Tumor stroma	Proven metastasis
Graham et al. 2017 [6]	Adenocarcinoma	Papillary and gland-like	—	Small, punctate, and round nuclei	Pale eosinophilic	—	—	ILN
Pindoria et al. 2016 [7]	Papillary cystadenocarcinoma	Papillary structures projecting into cystic spaces; cystic and solid sheets	Cuboid to columnar, polygonal	—	Pale eosinophilic to clear	Spermatic cord	—	Ipsilateral testis
Urabe et al. 2016 [13]	Adenocarcinoma	Nest-like and tubular pattern; lobulated proliferation	—	—	—	—	Fibrotic and inflammatory	No
Gupta et al. 2015 [8]	Mucinous adenocarcinoma	Cystic spaces; variably sized tubular glands with intraluminal papillae; complex tubulocystic structures with mucin; calcification and necrosis	Frank goblet cell differentiation	Nuclear stratification, moderate nuclear pleomorphism, coarse chromatin, and frequently prominent nucleoli; identified mitosis	Intracytoplasmic mucin	Periepididymal soft tissue, testis, rete testis and spermatic cord	—	No
Nozawa et al. 2014 [5]	Clear cell papillary cystadenocarcinoma	Solid nests and tubular structure; necrosis	—	Small round nuclei (a part); nuclear atypia and occasional mitosis (a part)	Clear to eosinophilic	Testicular capsule and surrounding soft tissues	—	No
Staník et al. 2012 [9]	Poorly differentiated adenocarcinoma	Microacinar and solid, sporadically cribriform; no necrosis	—	Mainly round with finely dispersed chromatin, with sporadic nuclei variability such as hyperchromasia, prominent nucleoli and monstrous nuclei; high mitosis	Large clear vacuoles without evident mucus secretion	Testis	Fibrous septa	RPLN
Soumarová et al. 2012 [10]	Adenocarcinoma	Tubular, papillary, tubulopapillary and cystopapillary structures alternating with solid structures	Cuboid, columnar and epitheloid	High atypical mitosis	Some contain clear cytoplasm	Endolymphatic, endovenous, (peri)endoneural and pseudocapsule tumour permeation	Pseudocapsules and incomplete fibrous septa	RPLN
Arisan et al. 2004 [14]	Small differentiated adenocarcinoma	Irregular adenoid structures; solid spherical or papillary pattern proliferation	Big	Pleomorphic vesicular nucleus, definite nucleolus; some mitosis	—	Seminal cord	—	No
Hayashi et al. 2003 [16]	Moderately differentiated adenocarcinoma	Cord- and nest-like or complex glandular pattern; necrosis	—	Hyperchromatic, pleomorphic; increased mitosis	—	Testis	—	No
Chauhan et al. 2001 [11]	Poorly differentiated adenocarcinoma	—	—	—	A strong PAS staining	Epididymal tubules	—	RPLN
Ganem et al. 1998 [3]	Well differentiated adenocarcinoma	Microglandular	—	—	—	Perineural space	—	No
Jones et al. 1997 [4]	Adenocarcinoma	NO. 1 + 2, variably sized, simple tubules or complex tubular glands with intraluminal papillae; necrosis (in one patient) NO. 3 + 4,large cysts contain lightly eosinophilic secretions and had complex, arborizing papillary structures projecting into them	NO. 1 + 2,cuboidal or rarely columnar NO. 3 + 4,columnar	NO. 1 + 2,mildly to moderately atypical nucleus, visible nucleoli; infrequent mitosis NO. 3 + 4,infrequent mitosis	NO. 1 + 2,clear or rarely lightly amphophilic NO. 3 + 4,lightly amphophilic, eosinophilic or clear cytoplasm	NO. 1 + 2,epididymal muscular wall, periepididymal soft tissue, or both. NO. 3 + 4,—	NO. 1 + 2,focally desmoplastic stroma NO. 3 + 4,—	NO. 1 + 4,RPLN NO. 2 + 3,No

ILN: inguinal lymph node; RPLN: retroperitoneal lymph node; — means that contents were not mentioned in the literatures.