A Case of Chronic Thrombocytopenia in a 17-Year-Old Female

Roger Riley, MD, PhD; Asad Khan, MD; Shella Pai, MS, SH(ASCP); Laura Warmke, MD; Marcus Winkler, MD; William Gunning, PhD


Lab Med. 2019;50(4):406-420. 

In This Article

Clinical and Laboratory Data

The patient initially had moderate thrombocytopenia and mild leukopenia but later developed mild anemia (Table 1). An assay for diepoxybutane (DEB)–induced chromosome breakage had a negative result, which was not supportive of a diagnosis of Fanconi anemia. A bone marrow aspirate and biopsy were inadequate for morphologic interpretation; however, cytogenetics analysis and fluorescence in situ hybridization (FISH) studies yielded no abnormal findings. Her peripheral blood film demonstrated moderate to severe thrombocytopenia with frequent gray hypogranular PLTs (Image 1). Electron microscopy (EM) revealed that all PLTs were devoid of α-granules and demonstrated a dilated open canalicular system; in contrast, δ (dense) granules were present in adequate numbers (5.48 δ-granules/PLT; reference range, 4–6 δ-granules/PLT) (Images 2A and 2B).

Image 1.

Photomicrograph of patient's peripheral blood film showing large hypogranular platelets (arrows) with dilated cisternae (Wright-Giemsa stain, 1000x).

Image 2.

Transmission electron microscopy of thin sections of platelets. A, Platelet from heathy individual with normal numbers of α- (long arrows) and δ (dense) granules (short arrows) (x30,000 magnification). B, Patient's platelet showing δ (dense) granule and absence of α-granules (x30,000).