Spiradenoma and Spiradenocylindroma With an Adenomatous or Atypical Adenomatous Component: A Clinicopathological Study of 6 Cases

Abstract

We report 5 cases of spiradenoma and 1 case of spiradenocylindroma, which, in addition to areas of conventional growth, manifested an adenomatous component. This consisted of compactly situated, well-developed glands having small round lumens lined by inner pale to eosinophilic cells and surrounded by an outer well-formed peripheral layer of myoepithelial cells, which reacted with a variety of myoepithelial cell markers. In 1 case, apocrine secretion was evident in the glandular part of the lesion. In 4 of the 6 cases, the adenomatous component was a minor but significant portion of the tumors, but in 2 cases it was extensive, comprising approximately 20% of the tumor area. In 1 of these 2 cases, the luminal epithelium showed atypia including rare, atypical mitotic figures. In addition, there were foci of glands showing myoepithelial cell loss. As this alteration was limited and fairly well circumscribed within the tumor bulk, we regard it as an "atypical adenomatous component," but we cannot exclude the possibility that this may represent an incipient apocrine carcinoma, despite uneventful follow-up. Three cases also manifested clear cell areas. Immunohistochemical studies demonstrated that myoepithelial proliferation and overgrowth accounted for the clear cell change in some of the lesions.

Adenoid Cystic Carcinoma-Like Pattern in Spiradenoma and Spiradenocylindroma: A Rare Feature in Sporadic Neoplasms and Those Associated With Brooke-Spiegler Syndrome

“…1A-C, 2, 3), whereas in other cases, a combination of all of 3 secretory products was encountered. Glands with a dual epithelial lining, including a peripheral continuous myoepithelial cell detectable at the light microscopic level as rarely seen in spiradenoma, 3,4 were not recognizable in these ACC-like areas. However, myoepithelial cell differentiation was proven immunohistochemically in the ACC-like foci (Fig.…”

“…On rare occasions, the neoplasms may display an adenomatous pattern of welldefined glands having a well-developed continuous outer myoepithelial cell layer. 3,4 Myoepithelial cells, although commonly encountered in classical spiradenoma and spiradenocylindroma, are not evident at the light microscopic level, but they are convincingly demonstrated by electron microscopy and immunohistochemistry. [5][6][7][8][9] Further morphologic variations include squamous, mucinous, and clear cell differentiation.…”

Skin type spiradenoma of the parotid gland with malignant transformation

“…Our review of the literature and investigation of our own cases of cutaneous spiradenocarcinoma indicate that al least 4 patterns of the malignant skin neoplasm can be recognized, namely, (1) salivary gland-type basal cell adenocarcinoma-like pattern, low grade; (2) salivary gland-type basal cell adenocarcinoma-like pattern, high grade; (3) sarcomatoid (metaplastic) carcinoma; and (4) invasive adenocarcinoma, not otherwise specified [44]. The latter variant is noteworthy because spiradenocarcinomas with an adenocarcinomatous component display highly atypical glands, some surrounded by an intact myoepithelial layer [45]. Myoepithelial differentiation in cutaneous spiradenoma is often detected immunohistochemically [46,47], but authentic glands with well-developed myoepithelial cells are extremely rare [48,45].…”

“…The latter variant is noteworthy because spiradenocarcinomas with an adenocarcinomatous component display highly atypical glands, some surrounded by an intact myoepithelial layer [45]. Myoepithelial differentiation in cutaneous spiradenoma is often detected immunohistochemically [46,47], but authentic glands with well-developed myoepithelial cells are extremely rare [48,45]. Malignant transformation of spiradenoma has also been reported in the breast [49,50].…”

Phenotype–genotype correlations for clinical variants caused by CYLD mutations

“…Spiradenomas rarely become malignant but can transform into spiradenocarcinomas [Cooper et al, 1985;Engel et al, 1991;Chou et al, 2004]. Hybrid tumors can also occur, such as spiradenocylindromas, which exhibit the characteristics of both cylindromas and spiradenomas [Kazakov et al, 2005;Kazakov et al, 2008;Pizinger and Michal, 2000].…”