---
schema_version: "secwatch.filing_event.v1"
accession: "0001447362-22-000050"
form_type: "8-K"
ticker: "CSTL"
cik: "0001447362"
company_name: "CASTLE BIOSCIENCES INC"
filed_at: "2022-03-17T23:59:59+00:00"
generated_at: "2026-06-26T21:57:56.550888+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.3
calibrated_materiality_score: 0.3
confidence: "high"
source: SEC EDGAR
---

# Castle Biosciences expands Phoenix office by 5,904 sq ft, extends lease through 2033

## Summary
- Expanded premises include Suite 170, adding 5,904 rentable sq ft for total ~17,820 sq ft.
- Lease term extended to 129 months following expansion completion; expiration approximately 2033.
- Base rent starts at $21.00/sq ft/yr ($31,185/month) with annual $0.50/sq ft increases through ~2033.
- Landlord provides $15.00/sq ft tenant improvement allowance ($88,560); Tenant pays any excess costs.
- Parking rights increase to 65 total spaces, including 5 covered reserved spaces, at no additional charge.

## SEC filing metadata
- accession: 0001447362-22-000050
- form_type: 8-K
- ticker: CSTL
- cik: 0001447362
- company_name: CASTLE BIOSCIENCES INC
- filed_at: 2022-03-17T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.3
- calibrated_materiality_score: 0.3
- confidence: high
- sec_items: 1.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1447362/000144736222000050/0001447362-22-000050-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1447362/000144736222000050/cstl-20220311.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001447362-22-000050
- JSON: https://secwatch.observer/filing/0001447362-22-000050.json
- Plain text: https://secwatch.observer/filing/0001447362-22-000050.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.