Authors: Srikar Yellapragada, Alexandros Graikos, Zilinghan Li, Kostas Triaridis, Tarak Nath Nandi, Ji Dong K Bai, Beatrice Knudsen, Tahsin Kurc, Prateek Prasanna, Rajarsi R. Gupta, Ravi K Madduri, Joel Saltz, Dimitris Samaras
Organizations: Stony Brook University · Argonne National Laboratory · University of Chicago · The University of Utah · The University of North Carolina at Chapel Hill
Whole-slide images (WSIs) are gigapixel-scale digital scans of histopathology tissue and serve as the primary basis for cancer diagnosis. Existing histopathology generative models operate at the patch scale, producing fixed-size tiles of at most 1024×1024 pixels which encompass only a small fraction of the WSI. In contrast, text reports for clinical diagnoses and slide-level diagnostic labels -- the supervision that exists at scale -- operate at the whole-slide level. We present BigCell, the first approach to generate coherent whole-slide histopathology images at native gigapixel resolution. BigCell trains a flow-matching transformer at 2048×2048 pixels on over 120,000 publicly available WSIs spanning multiple organ types. Conditioning on embeddings from pathology foundation models and using an inference-time sliding-window pipeline, BigCell generates coherent images of up to 32,768×32,768 pixels, outperforming prior tile generators on both tile-level and slide-level fidelity metrics. To make gigapixel synthesis practical, we introduce an adaptive scheduling strategy that prioritizes important slide regions, speeding up image generation by over 3\ttimes with minimal quality degradation. Furthermore, we propose the first text-to-image synthesis at 8k resolution by training a separate model that produces dense conditioning grids directly from pathology text reports. We demonstrate that augmenting with synthetic samples improves slide-level few-shot classification performance by up to 18% over baselines trained on real data.
Figures & tables
Figure 1: We present synthetic images generated using BigCell. Left: 32768 × 32768 images along with 2048 × 2048 crops, highlighting the realism achieved both at the macro-scale and cellular detail level. Right: Two 8192 × 8192 images per report generated from text. Best viewed zoomed in.
Figure 2: Overview of the BigCell pipeline. (a) We obtain a dense grid of conditioning embeddings either from a reference WSI or sampled using a model conditioned on text (CGM). This serves as the controllable blueprint that defines the large-scale structures of the whole-slide image. (b) The tile generator uses the local conditioning to predict how to transform the slide locally. (c) Using the tile generator on overlapping windows, we aggregate the per-window velocities into a global velocity field and iteratively denoise the noisy slide into a gigapixel image, allowing us to efficiently synthesize WSIs without explicitly training on their scale.
Slide-level Similarity
Patch-level Similarity
Fréchet Distance
Generator
TITAN↑
MOOZY↑
V2 mean ↑
V2 5th ↑
H1 mean ↑
H1 5th ↑
V2 FD ↓
H1 FD ↓
PixCell
. 941
. 900
. 778
. 632
. 667
. 509
1023
696
CytoSyn
.929
.864
.753
.502
.640
.457
895
604
MuPaD
.646
.755
.462
.258
.342
.196
981
641
LRDM
.531
.693
.513
.334
.395
.247
731
502
ZoomLDM
.708
.801
.646
.464
.477
.325
8 15
5 53
Table 1: Comparison at 8192 × 8192 resolution. V2: Virchow-2; H1: H-Optimus-1; FD: Fréchet distance (no test). ∗ : p<0.001 , two-sided paired Wilcoxon vs. best baseline ( N=100 ). Resolution- and data-matched comparisons are in Appendix E.2 .
Generator
Same organ↑
Same diagnosis↑
All three fields↑
PixCell
6 3%
4 2%
3 8%
CytoSyn
54%
26%
25%
MuPaD
41%
17%
17%
ZoomLDM
61%
40%
36%
LRDM
59%
31%
30%
BigCell
69%
46%
41%
Table 2: Report-level agreement at 8192 × 8192 resolution ( N=100 , same ROIs as Table 1 ): fraction of generated/reference pairs whose MedGemma-4B reports agree on the tissue of origin, the diagnosis, and all three fields (organ, malignancy, diagnosis).
Figure 3: Adaptive window scheduling compared with simple, fewer-step sampling and the full 38440 NFE baseline at 32k resolution (N=256), evaluated at r∈{0.05,0.09,0.25,0.41} . At r=0.25 , we obtain a 3.1 × speedup (15.6 h → 4.97 h on a single Intel Data Center GPU Max 1550).
TITAN
PRISM
Method
Sim
Recall@1
Recall@5
Sim
Recall@1
Recall@5
Real data (paired)
0.551
0.211
0.655
0.499
0.148
0.430
BigCell
0.487
0.169
0.655
0.454
0.106
0.387
Table 3: TITAN and PRISM CLIP-style similarity and report-to-image retrieval recall on 150 held-out reports. CGM-generated images approach the alignment of real data under both encoders.
Figure 7
Figure 5: Synthetic 8192 × 8192 image generated by BigCell from a pathology text report, showing extensive pancreatic ductal adenocarcinoma.
Appendix figures & tables14 assets
Supplementary material from the paper’s appendix.
Appendix
Step
Tensor
2048 × 2048 tile
32,768 × 32,768 canvas
Input / output image
image x
2048×2048×3
32768×32768×3
VAE encode / decode
latent z
256×256×32
4096×4096×32
UNI-2 on 256 × 256 patches
conditioning grid y
8×8×1536
128×128×1536
Denoising (per window)
velocity vθ(zt,t,y)
256×256×32
256×256×32
Appendix
Table 5: Tensor shapes in BigCell for a single 2048 × 2048 tile and a 32,768 × 32,768 canvas. At 32k, each sliding window operates on a 256×256×32 latent region with the corresponding 8×8×1536 slice of the conditioning grid.
Resolution
Batch size
Conditioning
lr
t schedule
256
4800
1×1536
2e-4
Uniform
512
2400
4×1536
1e-4
Uniform
1024
720
16×1536
1e-4
Shifted, α=3
2048
360
64×1536
1e-4
Shifted, α=3
Appendix
Table 6: Progressive training schedule for BigCell tile . We train for one epoch at each resolution, and initialize the model from the previous stage weights.
Component
BigCell tile
CGM
Optimizer
AdamW
AdamW
β1,β2
0.9, 0.999
0.9, 0.95
Weight decay
0
0
EMA decay
0.9999
0.9995
Gradient clipping
1.0
1.0
Warmup
5,000 steps (linear)
40 epochs (linear)
Appendix
Table 7: Training configuration for BigCell tile and CGM
Resolution
Batch size
Sec/Iter
Compute/Sample
1024
720
1.35
1.0 ×
2048
360
5.59
8.3 ×
4096
360
65
96 ×
Appendix
Table 8: Training cost across native resolutions, measured on the Intel GPU cluster. Cost scales quadratically, making training at 4096 impractical. The 4096 row is a single-iteration benchmark; we did not train a model at this resolution.
Figure 6: Effect of tile generator’s native resolution on 8192 × 8192 generation quality. Both slide-level and tile-level metrics improve with resolution, with diminishing returns beyond 1024.
Slide-level Similarity
Patch-level Similarity
Fréchet Distance
Generator
TITAN↑
MOOZY↑
V2 mean ↑
H1 mean ↑
V2 FD ↓
H1 FD ↓
Matched native resolution
PixCell-1024
.941
.900
.778
.667
1023
696
BigCell-1024
.952
.971
.849
.723
912
617
Matched native resolution, data, and compute
BigCell-summarizer-2048
.926
.868
.627
.505
1229
813
Appendix
Table 9: Resolution-matched comparisons at 8192 × 8192 resolution ( N=100 , same ROIs as Table 1 ). Top: BigCell and PixCell at the same 1024 native resolution. Bottom: BigCell against a model with identical backbone, data, sampler, and training budget that uses ZoomLDM’s summarizer-based conditioning.
Figure 7: Effect of window selection strategy on 8192 × 8192 generation quality. Our CFG importance-based strategy outperforms random selection across all metrics.
Field agreement
BigCell vs. reference
Chance
Same tissue of origin
85.9% [81.1, 89.6]
9.1% [7.7, 10.7]
Same diagnosis
72.2% [66.4, 77.3]
9.2% [7.4, 11.1]
All three fields identical
71.0% [65.1, 76.2]
6.0% [4.6, 7.7]
Appendix
Table 10: Report-level agreement at 32,768 × 32,768 resolution ( N=256 , full compute). Chance is the rate at which a real report matches the synthetic report of a different slide, averaged over all such pairings. 95% Wilson intervals in brackets.
Figure 8: Pathologist evaluation interface. Each trial shows an 8192 × 8192 image (real or synthetic) and four candidate reports (one of which is true). Pathologists indicate matching report(s) and classify the image as real or synthetic.
Figure 9: Qualitative comparison of 8192 × 8192 generation between BigCell tile and baselines. Top row: full 8k image. Bottom row: 2k crop from the boxed region.
Figure 10: Visualization of CFG-magnitude importance scores on two synthetic 8192 × 8192 images. Tissue regions receive high importance, while background regions receive low importance.
Figure 11: 32,768 × 32,768 pixel breast tissue image generated by BigCell (top), with progressive zoom-in crops from the marked regions (bottom).
Figure 12: 32,768 × 32,768 pixel lung tissue image generated by BigCell (top), with progressive zoom-in crops from the marked regions (bottom).
Figure 13: 32,768 × 32,768 pixel mesothelial tissue image generated by BigCell (top), with progressive zoom-in crops from the marked regions (bottom).
1Nhu Department of Electrical Engineering and Computer Science, University of California, Irvine · Department of Electrical & Computer Engineering, National University of Singapore · 3PuzzleLogic Pte Ltd, Singapore 229594, Singapore