Hemangioendothelioma with a Prominent Lymphoid Infiltrate Mimicking Follicular Dendritic Cell Tumor: Report of a Case
Bibliographic record
Abstract
Hemangioendothelioma is a vascular tumor with several different morphologic patterns that can include a component of ovoid or spindled cells, but generally lacks an inflammatory component. The combined morphologic and immunohistochemical features are generally sufficient to accurately diagnose this tumor and its many variants. We present a challenging lymphocyte-rich soft tissue lesion that was not recognized to be an unusual hemangioendothelioma until after several recurrences in the arm of a 63 year-old male, which was originally diagnosed as a follicular dendritic cell tumor instead. Local recurrence developed 3 and 11 years later with resections. The most recent tumor consisted predominantly of epithelioid spindled cells with moderate amounts of bubbly pale to eosinophilic cytoplasm with rare discrete cytoplasmic vacuoles, admixed with a prominent lymphoid infiltrate and occasional erythrocytes. The tumor cells were positive for keratin and vascular markers (CD31, CD34, and Factor VIII), but negative for follicular dendritic cell markers (CD21, CD23, CD35). Slides from the two previous excisions were re-analyzed, and showed the same morphologic and immunohistochemical features as the latest recurrence. The diagnosis was revised to recurrent lymphocyte-rich hemangioendothelioma. The patient is free of tumor at 7 years follow-up. This represents an unusual and potentially confusing pattern of hemangioendothelioma that is not previously well described in the literature. Vascular tumors should be included in the differential diagnosis of suspected dendritic cell tumors, even if a lymphocyte-rich infiltrate is present. Vascular as well as dendritic cell markers should be included in the immunohistochemical panel employed in their evaluation. Keyword: Hemangioendothelioma, lymphocyte rich, follicular dendritic cell, tumor.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.003 | 0.003 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.004 | 0.003 |
| Scholarly communication | 0.003 | 0.004 |
| Open science | 0.002 | 0.003 |
| Research integrity | 0.008 | 0.004 |
| Insufficient payload (model declined to judge) | 0.002 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".