NPIMap

Individual provider Active NPI

Marwan Massouh, MD

  • Hematology & Oncology Physician
  • Westlake, OH
National Provider Identifier
1508841669
Registry record updated Jul 13, 2026
On this page

Key facts

NPPES NPI Registry
Primary specialty
Hematology & Oncology PhysicianTaxonomy code 207RH0003X
License
35056179 Issued in OH
Practice address
29101 Health Campus Dr
Suite 260
Westlake, OH 44145-5270
Phone
(440) 808-6500
Fax
(440) 808-8865
NPI assigned
Dec 13, 2005
Last updated
Jul 13, 2026By the provider in NPPES
Sex
Male
Sole proprietor
No

NPPES NPI Registry

Updated by the provider on Jul 13, 2026

Registry information is reported by the provider to CMS and is not verified. About this source

Specialties & licenses 1

Specialty (taxonomy)CodeLicenseStatePrimary
Hematology & Oncology Physician 207RH0003X 35056179 OH Primary

Addresses

Primary practice location

29101 Health Campus Dr
Suite 260
Westlake, OH 44145-5270

Mailing address

29101 Health Campus Dr
Suite 260
Westlake, OH 44145-5270
Phone (440) 808-6500

Other identifiers 2

IdentifierTypeStateIssuer
000000212199OtherOHANTHEM
0848382MedicaidOH

Medicare participation

Medicare enrollment files
Medicare fee-for-service enrollment
Enrolled in OH, MT2 enrollments
Eligible to order & refer
  • Part B services
  • Medical equipment
  • Home health
  • Power mobility devices
  • Hospice
Green means eligible to order or refer.

Enrollment records 2

Enrollment IDStateProvider typePAC IDDetails
I20040129000186 OH Practitioner - Hematology/Oncology 6709785702 Reassigns benefits to 2 organizations
I20150921002541 MT Practitioner - Hematology/Oncology 6709785702 Reassigns benefits to 2 organizations

Care Compare profile

Medicare Care Compare
Specialty
Hematology/Oncology
Education
Other, 1982
Medicare assignment
Accepts the Medicare-approved amount as payment in full
Group practices

Practice addresses (Care Compare)

3004 Hayes Ave
Sandusky, OH 44870-5321
Phone (419) 609-1112

400 S Clark St
Butte, MT 59701-2328
Phone (406) 495-7260

Hospital & facility affiliations

National Provider Directory

National Provider Directory
Medicare enrollment (NPD)
Not enrolled
HHS exclusion list flag
CMS’s directory marks this NPI as on an HHS exclusion list; no matching OIG record was found. The OIG exclusions file (LEIE) holds no record for this NPI, and the directory does not say which list the flag comes from. How exclusions are shown Confirm with the OIG exclusions search.
Credentials
Doctor of Medicine

State licenses

LicenseStateTypeSpecialty
35056179OHMDHematology & Oncology Physician

Practice roles

OrganizationSpecialtyStatusNew patients
University Primary Care Practices Inc Current Accepting new patients
St. James Healthcare Current Accepting new patients
SCL Health Medical Group-Butte LLC CurrentSince Aug 1, 2017 Accepting new patients
St James Healthcare CurrentSince Sep 1, 2015 Accepting new patients
University Primary Care Practices Inc CurrentSince Oct 1, 2022 Accepting new patients
SCL Health Medical Group-Butte LLC CurrentSince Aug 1, 2017 Accepting new patients
Butte Pathology LLC Current Accepting new patients
University Primary Care Practices Inc CurrentSince Oct 1, 2022 Accepting new patients
Elkhorn Mountain Health Services Inc Past Accepting new patients
University Hospitals Medical Group Inc Past Accepting new patients

Locations

400 S Clark St
Butte, MT 59701
Phone (406) 495-7260

400 S Clark St
Ofc
Butte, MT 59701

11100 Euclid Ave
Cleveland Heights, OH 44106

158 W Main Rd
Ste 203
Conneaut, OH 44030
Phone (440) 285-2960

Interoperability endpoints

  • Direct secure messaging: mmassouh@direct.swgeneral.com
  • Direct secure messaging: mmassouh954904@wm.providencedirect.org

Organizations & group practices 12

Organizations this provider is connected to: Medicare benefit reassignments (the organization bills Medicare for this provider’s services), Care Compare group memberships, National Provider Directory roles and organizations whose NPPES authorized official is this provider.

Hospital & facility affiliations 11

Hospitals and other facilities this clinician is affiliated with according to Medicare Care Compare.

NPI Registry JSON

The complete NPPES record for this NPI in the NPI Registry API format.

{
    "created_epoch": "1134432000000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1783900800000",
    "number": "1508841669",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "29101 HEALTH CAMPUS DR",
            "address_2": "SUITE 260",
            "city": "WESTLAKE",
            "state": "OH",
            "postal_code": "441455270",
            "telephone_number": "440-808-6500",
            "fax_number": "440-808-8865"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "29101 HEALTH CAMPUS DR",
            "address_2": "SUITE 260",
            "city": "WESTLAKE",
            "state": "OH",
            "postal_code": "441455270",
            "telephone_number": "440-808-6500",
            "fax_number": "440-808-8865"
        }
    ],
    "practiceLocations": [],
    "basic": {
        "last_name": "MASSOUH",
        "first_name": "MARWAN",
        "name_prefix": "Mr.",
        "credential": "MD",
        "sole_proprietor": "NO",
        "sex": "M",
        "enumeration_date": "2005-12-13",
        "last_updated": "2026-07-13",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "207RH0003X",
            "taxonomy_group": "",
            "desc": "Internal Medicine, Hematology & Oncology",
            "state": "OH",
            "license": "35056179",
            "primary": true
        }
    ],
    "identifiers": [
        {
            "code": "01",
            "desc": "Other (non-Medicare)",
            "issuer": "ANTHEM",
            "identifier": "000000212199",
            "state": "OH"
        },
        {
            "code": "05",
            "desc": "MEDICAID",
            "issuer": null,
            "identifier": "0848382",
            "state": "OH"
        }
    ],
    "endpoints": [],
    "other_names": []
}

Other providers in Westlake, OH

Sources for this page

Verify at the official NPI Registry.