title: Tubular adenoma and syringocystadenoma papilliferum: a reappraisal of their relationship. An interobserver study of a series, by a panel of dermatopathologists.
abstract: Tubular adenoma (TA) and syringocystadenoma papilliferum (SCAP) may show histopathological overlap, with some lesions having features of both neoplasms (SCAP + TA). TA has been recently suggested to represent a carcinoma. Four observers blindly assessed 67 cases of TA, SCAP, and their lookalikes (poroma, apocrine adenoma, apocrine carcinoma; all lesions focally featuring a pseudopapillary pattern), and classified the lesions into one of four categories: (1) TA, (2) SCAP, (3) SCAP + TA, and (4) others. Lesions were also classified as benign or malignant. In only 29 cases was there unanimous agreement among the four observers, who classified 22 lesions as TA, three as SCAP, and four cases as others. Of the 38 cases where there was interobserver diagnostic variation, in 30, the diagnosis varied between TA or SCAP or SCAP + TA; the remainder fell in the others category. Analysis of the factors leading to interobserver variability indicated that diagnostic problems occurred when there were any of the following: epidermal acanthosis, papillomatosis, connection of the neoplastic tubules to the overlying epidermis and/or follicular infundibula, and plasma cell infiltration. These features accounted for the morphological overlap between TA and SCAP. All observers agreed that the lesions were benign; the only apocrine carcinoma included was recognized as such by all observers. From the study, it was concluded that TA may arise in the deep dermis without any epidermal connection, or, in other cases, it may be more superficially located with or without an epidermal connection. It may be reasonably inferred that, possibly as a response to infection, there may be accompanying plasma cells and variable acanthosis and papillomatosis, such that the appearances are those of "pure" SCAP, or lesions may have features "intermediate" or overlapping between TA and SCAP.
authors.affiliation: Sikl's Department of Pathology, Charles University, Medical Faculty Hospital, Pilsen, Czech Republic. kazakov@medima.cz
authors.forename: Dmitry V
authors.initials: DV
authors.lastname: Kazakov
authors.forename: Michele
authors.initials: M
authors.lastname: Bisceglia
authors.forename: Eduardo
authors.initials: E
authors.lastname: Calonje
authors.forename: Markus
authors.initials: M
authors.lastname: Hantschke
authors.forename: Heinz
authors.initials: H
authors.lastname: Kutzner
authors.forename: Thomas
authors.initials: T
authors.lastname: Mentzel
authors.forename: Michal
authors.initials: M
authors.lastname: Michal
authors.forename: Petr
authors.initials: P
authors.lastname: Mukensnabl
authors.forename: Dominic V
authors.initials: DV
authors.lastname: Spagnolo
authors.forename: Arno
authors.initials: A
authors.lastname: Rütten
authors.forename: Christian
authors.initials: C
authors.lastname: Rose
authors.forename: Carmelo
authors.initials: C
authors.lastname: Urso
authors.forename: Marina
authors.initials: M
authors.lastname: Vazmitel
authors.forename: Bernhard
authors.initials: B
authors.lastname: Zelger
mesh_terms: D006607:Adenoma, Sweat Gland / Q000145:classification / Q000175:diagnosis*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003537:Cystadenoma / Q000145:classification / Q000175:diagnosis*; D003880:Dermatology / Q000379:methods; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000175:diagnosis*; D015588:Observer Variation; D010336:Pathology / Q000379:methods; D013544:Sweat Gland Neoplasms / Q000145:classification / Q000175:diagnosis*