Malignant T cells rim around adipocytes Prominent karyorrhexis/apoptosis and angioinvasion Ancillary Tests • Immunohistochemistry: TCRδ1(+), βF1(-), CD56(+), CD4(-), CD8(-) • EBER(-), cytotoxic markers (+) • T-cell receptor gene rearrangement Top Differential Diagnoses • Subcutaneous…
Pilar type (piloleiomyoma) arises from arrector pili Genital type arises from specialized genital smooth muscle Etiology/Pathogenesis • Hereditary leiomyomatosis and renal cell cancer syndrome Multiple leiomyomas of skin and uterus Subset…
Inflammatory component shows variable mixtures of lymphoplasmacytic cells, eosinophils, neutrophils, and histiocytes • Areas with prominent myxoid change • Scattered enlarged atypical tumor cells, some with macronucleoli Cells with macronucleoli resemble Reed-Sternberg…
Elongated and anastomosing rete ridges Atypical basal cells with hyperchromatic-staining nuclei Subtle abnormal maturation (large, eosinophilic keratinocytes) Whorling and keratin pearl formation Usually associated with LS&A Preferential association with HPV-unrelated…
Skin metastases: Nodule, often pigmented, may be ulcerated, multiple or solitary Nodal metastases: Usually in regional lymph nodes Blue nevus-like melanoma: Blue macule/papule, often near original site of primary melanoma…
Most patients have good prognosis, with only minority of cases progressing to systemic disease or death Microscopic • Severely atypical/borderline Spitz tumor Typically, large and deep cellular compound melanocytic tumors May…
Genes implicated include PTCH1 (Gorlin syndrome), TP53, SOX9, BMI1, BAX, RMRP Clinical Issues • Extremely common: Most common cancer in humans • Most common in head and neck region (up to…
Usually presents on scalp in infancy, often at birth Presents as yellowish flat to warty plaque; enlarges during puberty • Basaloid follicular hamartoma Usually presents in adults Microscopic • Nevus sebaceus Abnormalities…
Represent < 0.5% of all oral malignancies • Mean in 6th-7th decades • M > F (2.5-3:1) • Hard palate and maxillary alveolus are most common sites of involvement (~ 80%) • Cervical lymph…
