- Spitz melanocytoma (previously atypical Spitz tumor) - Microphthalmia-associated transcrip-tion factor (MITF) pathway-activated melanocytic tumors, see below • Immunohistochemistry can aid in diagnosis: - Loss of expression of PrkAr1a in some PEM - Diffuse nuclear β-catenin, nuclear LEF1 in Wnt-activated deep pene-

y Spitz nevi, atypical Spitz tumor (AST) and malignant Spitz tumor (MST): • Now recognized as a spectrum of tumors characterized by enlarged, epithelioid or spindled melanocytes mimicking those of melanoma; however, genetically distinct from melanomas, blue nevi, deep penetrating nevi and BAP1-inactivated nevi. • Spitz nevi are generally ...

2020年12月9日 · Lung tumor - Atypical carcinoid. Complete surgical resection is the most efficient treatment for localized disease and has a significant impact on prognosis (Lung Cancer 2020;139:94, Chest 2017;151:1141, NCCN: NCCN Guidelines - Neuroendocrine and Adrenal Tumors [Accessed 11 November 2020])

2021年8月30日 · Scalp or heel lesion with marked nuclear atypia, numerous mitotic figures, some atypical and necrosis Variable epithelioid tumor cells (Clin Lab Med 2011;31:345) Clear cell sarcoma: EWSR1 rearrangement (Histopathology 2004;45:433) Atypical cellular blue nevus (Arch Pathol Lab Med 2011;135:327): Cellular blue nevus

Mostly indolent; some may exhibit atypical histologic features Rare metastatic potential in lesions with atypical features (Eur J Dermatol 2014;24:594, Cancers (Basel) 2021;13:3066, J Cutan Pathol 2020;47:1150, Biology (Basel) 2022;11:460)

2022年4月14日 · Mutation / deletion of p16 tumor suppressor gene rarely in dysplastic nevus Altered expression of p53 Increased microsatellite instability in dysplastic nevus; not seen in benign nevus Some dysplastic nevi have deletion in p16 encoding chromosomal region 9p21 Usually diploid 24% have high risk mucosal HPV by PCR (Br J Dermatol 2005;152:909)

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2013年3月1日 · Compound nevus and spindle cell Spitz nevus (J Dermatol 2000;27:233) Cellular blue nevus in reticular dermis, overlying compound melanocytic nevus with transition to melanoma in situ ( Am J Dermatopathol 1991;13:169 )

2023年5月3日 · No mitoses are seen. These features are consistent with a typical carcinoid lung tumor. Ki67 immunostaining, counter to well differentiated neuroendocrine tumors from the gastrointestinal tract, is not essential to grade the tumor. The difference between typical and atypical tumor relies on mitosis count and the presence of necrosis.

BAP1 IHC: low expression (tumor proportion score 10%) BAP1 IHC is a prognostic test in uveal melanoma. Classification is as follows: if < 33% of tumor nuclei are positive, classify as low. If ≥ 33% are positive, classify as high. The tumor proportion score is estimated by manual quantification or digital image analysis.