Atypical cytomorphology of Gaucher cells is frequently seen in bone marrow smears from untreated patients with Gaucher disease type 1.

INTRODUCTION Gaucher cells (GCs), the lipid-laden storage macrophages, are the pathologic hallmark of Gaucher disease (GD). They are typically 20-100 μm in diameter with eccentrically placed nuclei and cytoplasm with characteristic crinkles and striations. A few previous observations have indicated that sometimes GD patients may display morphology of GCs which is different from this classical description. The aim of our study was to explore the morphological polymorphism of GCs in patients with untreated GD type 1 (GD1). MATERIAL AND METHODS May-Grünwald Giemsa stained bone marrow smears (BM-S) from 6 patients with sporadic GD1 were analysed; each patient sample consisted of two slides where all GCs and non-Gaucher cell macrophages were counted. We have defined for the study purposes and examined the following features of GCs which were considered as atypical: (1) foamy cytoplasm, (2) centrally placed nucleus, (3) cell diameter > 100 μm, (4) multinuclearity, (5) syncytial morphology, (6) unusually large cytoplasmic projections, and (7) apparent haemophagocytosis. RESULTS All analysed patients showed 22-40% GCs with atypical cytomorphology (median 29%). The median number of atypical features of GCs was 10 per patient (range 6-13). Multinuclearity was the most common atypical feature of GCs, followed by erythrophagocytosis and foamy cytoplasm. There was a strong positive correlation between erythrophagocytosis and foamy cytoplasm in GCs (Spearman's rank correlation coefficient: 0.9). Although majority of atypical GCs had one atypical feature, there was a considerable amount of GCs presenting ≥ 2 atypical features. CONCLUSIONS Untreated patients with GD1 often show a considerable proportion of GCs with atypical cytomorphology. The knowledge of possible atypical variant forms of GCs can contribute to a quicker and accurate diagnosis of GD, and minimize the risk for misdiagnosis. To the best of our knowledge, this is the first published report on atypical cytomorphology of GCs in untreated patients with GD1.