Dysplastic follicular dendritic cells in hyaline-vascular Castleman disease: a rare occurrence creating diagnostic difficulty.
Follicular dendritic cell (FDC) proliferations and dysplastic FDCs can be seen in Hyaline-vascular Castleman disease (HVCD). The association between HVCD and FDC sarcoma is well-documented; dysplastic FDCs may be precursors to FDC sarcoma. Herein, we describe a case of HVCD with strikingly large and dysplastic FDCs, which raised the differential of Hodgkin lymphoma and other neoplasms. Scattered dysplastic FDCs were predominantly in germinal centers and mantle zones, and rarely in interfollicular areas. Although occasional germinal centers contained increased FDCs, no mass forming proliferations were present to suggest FDC sarcoma. Immunostaining demonstrated that the atypical FDCs expressed CD21, clusterin and CXCL13, but not CD23, S100, pankeratin or CD30; they aberrantly expressed epidermal growth factor receptor (EGFR). The present case demonstrates that dysplastic FDCs may be present as isolated cells that require immunophenotyping to distinguish them from malignant entities with similar morphologic features. A variety of FDC markers is required to confirm their origin as the expression of any single marker is not assured, as occurred in this case. Pathologists need be aware of FDC proliferations in HVCD because of their association with FDC sarcoma. Aberrant EGFR expression by dysplastic FDCs may indicate that they are pre-neoplastic and necessitate long-term patient follow-up.
Department of Pathology, University of Texas Health Science Center, San Antonio, TX, USA.
Edward A
http://orcid.org/0000-0002-1305-4046
EA
Medina
Department of Pathology, University of Texas Health Science Center, San Antonio, TX, USA.
Neil E
NE
Fuehrer
Department Otolaryngology-Head & Neck Surgery, University of Texas Health Science Center, San Antonio, TX, USA.
Frank R
FR
Miller
Department of Pathology, University of Texas Health Science Center, San Antonio, TX, USA.
Marsha C
MC
Kinney
Department of Pathology, University of Texas Health Science Center, San Antonio, TX, USA.
Russell A
RA
Higgins
D000328:Adult; D015415:Biomarkers / Q000032:analysis; D005871:Castleman Disease / Q000175:diagnosis* / Q000473:pathology*; D020566:Dendritic Cells, Follicular / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006689:Hodgkin Disease / Q000175:diagnosis; D006801:Humans; D006818:Hyalin / Q000378:metabolism; D007150:Immunohistochemistry
D015415:Biomarkers
dysplastic FDCs; follicular dendritic cell sarcoma; follicular dendritic cells; hyaline vascular Castleman disease