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Westside Hematology Oncology Inc

Hematology & Oncology Physician in Westlake, OH · enumerated 2006 · authorized official Marwan Massouh, President.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1376650606

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Registry record

Entity type Organization (Type 2)
Legal business name Westside Hematology Oncology Inc
Practice address 29101 Health Campus Dr, Ste 260, Westlake, OH, 44145
Phone (440) 808-6500
Fax (440) 808-8865
Enumeration date Aug 24, 2006
Last updated in NPPES Aug 22, 2020

Taxonomy & classification

207RH0003X Hematology & Oncology Physician Allopathic & Osteopathic Physicians · License 35056179M (OH) Primary

Authorized official

Name Marwan Massouh
Title President
Phone (440) 808-6500

Other identifiers

Identifier Type State Issuer
0848382 Medicaid OH -
000000212199 Other OH ANTHEM

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

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Frequently asked questions

What is the NPI number for Westside Hematology Oncology Inc?
The NPI for Westside Hematology Oncology Inc is 1376650606, a Type 2 (organization) record in the CMS NPPES registry.
Who is the authorized official for Westside Hematology Oncology Inc?
NPPES lists Marwan Massouh (President) as the authorized official for this organization.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2020-08-22.