Department of Dermatology and Dermatologic Surgery, Tufts Medical Center, Boston, MA 02111, USA.
Dermatol Surg. 2012 Sep;38(9):1456-60. doi: 10.1111/j.1524-4725.2012.02507.x. Epub 2012 Jun 26.
Squamous cell carcinoma (SCC) in situ (SCCIS) is often treated without any pathologic confirmation of tumor clearance. It is unclear how often an invasive SCC is harbored within a lesion in which the initial biopsy demonstrated SCCIS because of inadequate sampling. This study examines the final histologic diagnosis of cases in which the initial biopsies were diagnosed as SCCIS and evaluates factors that may correlate with a histologic upstaging of the diagnosis.
We prospectively recruited 29 consecutive patients with biopsy-proven SCCIS sent for Mohs micrographic surgery (MMS). Each tumor underwent MMS, and the central blocks of the Mohs debulking specimens were horizontally sectioned at 30-μm intervals until exhausted. A fellowship-trained Mohs surgeon and a board-certified dermatopathologist processed and examined these sections to determine the final histologic diagnosis of the tumor.
Of the 29 subjects with biopsy-proven SCCIS, nine were found to harbor invasive SCC on final histology. Of the remaining lesions, seven had residual SCCIS, whereas the rest exhibited only actinic keratoses or scars. Approximately 31% of lesions showed evidence of invasive SCC. Correlating the clinical characteristics of the lesions with their corresponding final histologic diagnoses, the lesions harboring invasive SCC were more likely to demonstrate clinical signs of residual tumor (scales and papular changes) and be larger than 1.4 cm in diameter.
Our experience at a single institution in the northeastern United States may not be reflective of a wider population. There is also a possible referral bias, because only lesions with high clinical suspicion for invasive SCC were referred for MMS.
Although biopsy-proven SCCIS is often treated with modalities that are best suited for superficial disease and do not involve a final pathologic confirmation of clearance (e.g., cryotherapy, electrodesiccation and curettage), this study demonstrated that up to 31% of biopsy-proven SCCIS lesions may harbor invasive SCC. Clinical signs of residual tumor and a diameter larger than 1.4 cm are statistically significant predictors of underlying invasive SCC. These data suggest that treatment modalities that include histologic control of tumor removal should also be strongly considered for the treatment of select biopsy-proven SCCIS meeting the above criteria.
原位鳞状细胞癌 (SCCIS) 通常在未经任何肿瘤清除病理确认的情况下进行治疗。由于取样不足，初始活检诊断为 SCCIS 的病变中，隐匿浸润性 SCC 的频率尚不清楚。本研究检查了初始活检诊断为 SCCIS 的病例的最终组织学诊断，并评估了可能与诊断组织学升级相关的因素。
我们前瞻性招募了 29 名经活检证实为 SCCIS 并接受 Mohs 显微手术 (MMS) 的连续患者。每个肿瘤均接受 MMS 治疗，并在耗尽前以 30μm 的间隔将 Mohs 切除标本的中央块水平切片。一名接受过 fellowship培训的 Mohs 外科医生和一名 board-certified 皮肤科病理学家处理和检查这些切片，以确定肿瘤的最终组织学诊断。
在 29 名经活检证实为 SCCIS 的患者中，有 9 名患者在最终组织学上发现有浸润性 SCC。其余病变中，有 7 例仍有 SCCIS，其余均仅表现为光化性角化病或瘢痕。约 31%的病变有浸润性 SCC 的证据。将病变的临床特征与相应的最终组织学诊断进行关联，隐匿浸润性 SCC 的病变更有可能表现出残留肿瘤的临床迹象（鳞屑和丘疹性改变），且直径大于 1.4cm。
我们在位于美国东北部的单一机构的经验可能无法反映更广泛的人群。也可能存在转诊偏倚，因为只有高度怀疑浸润性 SCC 的病变才被转诊接受 MMS。
尽管活检证实的 SCCIS 通常采用最适合治疗浅表疾病的方法进行治疗，且无需最终病理确认清除（例如，冷冻疗法、电干燥和刮除术），但本研究表明，多达 31%的活检证实的 SCCIS 病变可能隐匿有浸润性 SCC。残留肿瘤的临床迹象和直径大于 1.4cm 是隐匿性浸润性 SCC 的统计学显著预测因子。这些数据表明，对于符合上述标准的选定活检证实的 SCCIS 病变，应强烈考虑包括肿瘤切除的组织学控制在内的治疗方法。
