Zhang M Lisa, Sabatino Marlena E, Castillo Carlos Fernandez-Del, Mattia Anthony R, Chebib Ivan
Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts, USA.
Harvard Medical School, Boston, Massachusetts, USA.
Diagn Cytopathol. 2023 May;51(5):E164-E169. doi: 10.1002/dc.25114. Epub 2023 Feb 10.
Fine-needle aspiration (FNA) is a minimally invasive and effective modality to diagnose pancreatic ductal adenocarcinoma. However, some histologic subtypes of ductal adenocarcinoma are rarely encountered and challenging to diagnose on FNA/small biopsies. To date, cytohistologic features of pancreatic sarcomatoid undifferentiated carcinoma with heterologous elements have not been thoroughly described. An 83-year-old man with lower back pain was found to have an incidental pancreatic neck mass. FNA biopsy of the mass showed rare markedly atypical, large, pleomorphic cells in a background of abundant calcifications/bone formation without areas of conventional adenocarcinoma. A diagnosis of "Malignant neoplasm with osteosarcomatous differentiation" was rendered on the FNA specimen. Subsequently, a Whipple resection revealed a 4.1 cm lobulated, calcified pancreatic mass. Microscopic examination showed a heavily calcified/ossified mass with adjacent areas of a highly cellular malignant spindle cell proliferation and admixed large, pleomorphic tumor cells; no background conventional adenocarcinoma was identified. Cytokeratin immunostains MNF116 and CK19 were positive in a large subset of the malignant spindle cells, and AE1.3/CAM5.2 showed patchy weak staining. Molecular testing revealed mutations in KRAS, TP53, BRCA2, NTRK3, EPHA2, MYD88, and CBL. No reportable fusions were detected. The final diagnosis was "Sarcomatoid undifferentiated carcinoma with heterologous elements (osteosarcomatous differentiation)." Definitive diagnosis of extremely rare subtypes of ductal adenocarcinoma is challenging on FNA biopsies. In this case, cytologic evaluation was helpful in making an early diagnosis of a malignant neoplasm with highly unusual features, prompting appropriate triage and early surgical resection of a sarcomatoid undifferentiated carcinoma with prominent osteosarcomatous differentiation.
细针穿刺抽吸活检（FNA）是诊断胰腺导管腺癌的一种微创且有效的方法。然而，导管腺癌的一些组织学亚型很少见，通过FNA/小活检进行诊断具有挑战性。迄今为止，具有异源性成分的胰腺肉瘤样未分化癌的细胞组织学特征尚未得到充分描述。一名83岁的男性因下背部疼痛偶然发现胰腺颈部肿块。对该肿块进行FNA活检显示，在大量钙化/骨形成的背景下，罕见明显非典型的大的多形性细胞，无传统腺癌区域。FNA标本诊断为“具有骨肉瘤样分化的恶性肿瘤”。随后，进行了胰十二指肠切除术，发现一个4.1厘米分叶状、钙化的胰腺肿块。显微镜检查显示，一个重度钙化/骨化的肿块，相邻区域有高度细胞性的恶性梭形细胞增殖，并混有大的多形性肿瘤细胞；未发现背景传统腺癌。细胞角蛋白免疫染色MNF116和CK19在大部分恶性梭形细胞中呈阳性，AE1.3/CAM5.2呈散在弱阳性。分子检测显示KRAS、TP53、BRCA2、NTRK3、EPHA2、MYD88和CBL存在突变。未检测到可报告的融合。最终诊断为“具有异源性成分（骨肉瘤样分化）的肉瘤样未分化癌”。通过FNA活检明确诊断导管腺癌的极罕见亚型具有挑战性。在本病例中，细胞学评估有助于早期诊断具有高度异常特征的恶性肿瘤，促使对具有显著骨肉瘤样分化的肉瘤样未分化癌进行适当的分类和早期手术切除。
