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.

Syringocystadenocarcinoma Papilliferum In Situ–Like Changes in Extramammary Paget Disease: A Report of 11 Cases

“…A similar phenomenon may be seen in other vulvar lesions 18 and also in cutaneous adnexal neoplasms, to wit tubular adenomas, which when acquiring a communication with the outside environment may develop appearances indistinguishable from syringocystadenoma papilliferum. 19 Lending further support to the reactive (hyperplastic) nature of the epidermal proliferative changes was the case in this series that demonstrated areas resembling ESFA. This lesion is considered by many to be a benign eccrine neoplasm but an alternative view is that it represents a reactive process involving the epidermis and eccrine ducts.…”

Lesions of the Lacrimal Caruncle With an Emphasis on Oncocytoma

“…33 They occur most commonly on the scalp but may be present at other sites. 34,35 Luminal cells are columnar with decapitation secretion, 33 and the tubules are embedded in a fibrotic stroma, 36 2 features that help differentiate them from oncocytomas. They stain similarly to oncocytomas, with luminal cells expressing cytokeratin, 37 Epithelial membrane antigen (EMA), CEA, and GCFDP-15, and peripheral cells expressing S100 protein.…”

Lipomatous apocrine adenoma with syringocystadenoma papilliferum arising from the external auditory canal

“…SCAP was previously reported to be often associated with pre-existing nevus sebaceous [7], and morphologic features of nevus sebaceous seldom existed in SCAP with TA [1]. No nevus sebaceous is seen in our case.…”

“…TA or SCAP was reported to have certain relationship with human papillomavirus infection [9] and a human papillomavirus induced non-neoplastic process leading to TA or SCAP was also speculated by some authors [1]. Warty surface or koilocytotic feature is not seen in our case.…”

“…Exostosis and squamous cell carcinomas are the most commonly-encountered benign and malignant tumors, respectively. Tubular adenoma (TA), also named as tubular apocrine adenoma, tubular syringoadenoma, or tubulopapillary hidradenoma [1,2], was first reported as a new entity by Landry and Winkelmann in 1972 [3]. Since then, less than one hundred cases of tubular adenoma were reported in the English literature [4].…”