Ball Nigel J, Tanhuanco-Kho Grace
Departments of Pathology and Dermatology, The University of British Columbia and Vancouver General Hospital, 855 West 12th Avenue, Vancouver, British Columbia, Canada.
J Cutan Pathol. 2007 Aug;34(8):612-9. doi: 10.1111/j.1600-0560.2006.00674.x.
Merkel cell carcinoma (MCC) is a basaloid cutaneous neoplasm that may be mistaken for basal cell carcinoma (BCC).
Thirty MCCs were examined for areas that histologically resembled BCC.
One of the histologic features of BCC (either a mucinous stroma or stromal artifactual retraction) was identified in all MCCs. A mucinous stroma was found in 28 MCCs (93%), stromal artifactual retraction in 27 (90%), mucin-containing gland-like spaces within tumor nests in 8 (27%), focal peripheral palisading in 8 (27%), epidermal involvement in 3 (10%) and dystrophic calcification in 1 MCC (3%). The cytologic features and absence of widespread peripheral palisading were the most reliable discriminators between MCC and BCC on routine sections. Squamous cell carcinoma was identified in four cases (13%). Two cases (7%) contained pagetoid intraepidermal spread (IES) of MCC. In one case, there was IES over the entire epidermal surface associated with intranuclear clearing, resembling the intranuclear cytoplasmic inclusions (INI) common in melanocytic tumors. INI were identified in six MCCs (20%).
MCCs frequently contain areas that histologically resemble BCC and other more common cutaneous malignancies. This can lead to diagnostic errors, particularly in small fragmented curettage specimens or frozen sections.
默克尔细胞癌（MCC）是一种基底样皮肤肿瘤，可能会被误诊为基底细胞癌（BCC）。
对30例MCC进行检查，观察其组织学上类似BCC的区域。
在所有MCC中均发现了BCC的一种组织学特征（黏液性间质或间质人为收缩）。28例MCC（93%）发现有黏液性间质，27例（90%）有间质人为收缩，8例（27%）肿瘤巢内有含黏液的腺样间隙，8例（27%）有局灶性周边栅栏状排列，3例（10%）有表皮受累，1例MCC（3%）有营养不良性钙化。在常规切片上，细胞学特征和缺乏广泛的周边栅栏状排列是MCC与BCC之间最可靠的鉴别点。4例（13%）确诊为鳞状细胞癌。2例（7%）存在MCC的派杰样表皮内播散（IES）。1例中，整个表皮表面均有IES，并伴有核内空晕，类似于黑素细胞肿瘤中常见的核内胞质包涵体（INI）。6例MCC（20%）发现有INI。
MCC常含有组织学上类似BCC和其他更常见皮肤恶性肿瘤的区域。这可能导致诊断错误，尤其是在小的碎刮标本或冰冻切片中。
