title: High Relative Expression of Pannexin 3 (PANX3) in an Axillary Sweat Gland Carcinoma With Osteosarcomatous Transformation.
abstract: Primary cutaneous sweat gland carcinomas (SGCs) are rare tumors that commonly involve axillae, have a high local recurrence rate, and rarely show sarcomatoid transformation. A 68-year-old man presented with rapid enlargement of a previously stable, asymptomatic pea-sized nodule in the left axilla. Initial excision (with positive surgical margins) at another institution showed characteristic histologic features of a high-grade osteosarcoma and molecular analysis using a 92-gene real-time quantitative reverse transcription-polymerase chain reaction assay confirmed a diagnosis of osteosarcoma with 96% certainty. Notably, the molecular assay demonstrated consistently high relative expression of pannexin 3 (PANX3), a gene involved in normal osteoblast differentiation which, when highly expressed, strongly predicts osteosarcoma per the assay's algorithm. However, on further histologic review, the tumor also contained focal cystic areas, nests, and ducts composed of malignant epithelial cells reminiscent of SGC; these areas directly transitioned into the osteosarcomatous component and were strongly positive for pancytokeratin, CK7, and p63. Within 2 weeks, the lesion recurred and grew rapidly, prompting complete resection, histologic sections of which showed high-grade osteosarcoma without residual epithelial elements. This is the fifth report, to our knowledge, of osteosarcomatous transformation in a SGC, and the only report to date including molecular data. This case demonstrates that osteosarcoma arising from a SGC has a similar molecular profile to de novo primary osteosarcoma of bone. It also emphasizes the importance of histopathologic findings as the established diagnostic gold standard and the need to interpret molecular results within the clinical context.
authors.affiliation: *Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN; Departments of †Pathology, ‡Dermatology, and §Radiology, University of Arkansas for Medical Sciences, Little Rock, AR; ¶Division of Hematology/Oncology, Department of Internal Medicine, University of Arkansas for Medical Sciences, Little Rock, AR; Departments of ‖Orthopedic Surgery and **Pathology, University of Arkansas for Medical Sciences, Little Rock, AR.
authors.forename: Ryan C
authors.initials: RC
authors.lastname: Romano
authors.forename: Jerad M
authors.initials: JM
authors.lastname: Gardner
authors.forename: Sara C
authors.initials: SC
authors.lastname: Shalin
authors.forename: Roopa
authors.initials: R
authors.lastname: Ram
authors.forename: Rang
authors.initials: R
authors.lastname: Govindarajan
authors.forename: Corey O
authors.initials: CO
authors.lastname: Montgomery
authors.forename: Jasen H
authors.initials: JH
authors.lastname: Gilley
authors.forename: Richard W
authors.initials: RW
authors.lastname: Nicholas
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000235:genetics; D001706:Biopsy; D002471:Cell Transformation, Neoplastic / Q000737:chemistry* / Q000235:genetics / Q000473:pathology; D017024:Chemotherapy, Adjuvant; D017630:Connexins / Q000032:analysis* / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000737:chemistry / Q000556:secondary; D008207:Lymphatic Metastasis; D008297:Male; D009364:Neoplasm Recurrence, Local; D012516:Osteosarcoma / Q000737:chemistry* / Q000556:secondary; D060888:Real-Time Polymerase Chain Reaction; D012086:Reoperation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013544:Sweat Gland Neoplasms / Q000737:chemistry* / Q000235:genetics / Q000473:pathology / Q000601:surgery; D013997:Time Factors; D016896:Treatment Outcome; D015854:Up-Regulation
chemical_list: D014408:Biomarkers, Tumor; D017630:Connexins; C492766:PANX3 protein, human