<Page>
EXHIBIT 3.59
FILED
JAN 12 2001
OKLAHOMA SECRETARY
OF STATE
AMENDED
CERTIFICATE OF INCORPORATION
OF
ANATOMIC PATHOLOGY SERVICES, P.C.
TO THE SECRETARY OF STATE OF THE STATE OF OKLAHOMA:
The undersigned corporation (this "corporation"), an Oklahoma corporation,
for the purpose of amending its Certificate of Incorporation pursuant to Section
1077 of the Oklahoma General Corporation Act (the "Act"), hereby certifies:
ARTICLE ONE
NAME
The name of this Corporation is Anatomic Pathology Services, Inc.
ARTICLE TWO
REGISTERED OFFICE AND AGENT
The address of its registered office in the State of Oklahoma is 2915 United
Founders Boulevard, is the City of Oklahoma City, County of Oklahoma, and the
name of its registered agent at such address is Corporation Service Company
ARTICLE THREE
NATURE OF BUSINESS; PURPOSES
The nature of the business and purposes to be conducted or promoted are:
To engage in any lawful act or activity for which corporations may be
organized under the Oklahoma General Corporation Act, or any act amendatory
thereof, supplemental thereto or substituted therefore.
To manufacture, purchase or otherwise acquire, invest in own, mortgage,
pledge, sell, assign and transfer or otherwise dispose of trade deal in and deal
with goods, wares and merchandise and personal property of every class and
description.
To acquire and pay for in cash, stock or bonds of this Corporation or
otherwise the goodwill, rights, assets and property, and to undertake or assume
the whole or any part of the obligations or liabilities of any person, firm or
associations or corporation.
To acquire, hold use sell assign lease grant licenses in respect of
mortgage or otherwise dispose of letters patent of the Untied States or any
foreign country, patent rights,
<Page>
licenses and privileges, inventions, improvements, and process copyrights
trademarks and trade names relating to or useful in connection with any business
of the Corporation.
To acquire by purchase, subscription or otherwise, and to receive, hold own
guarantee sell, assign, exchange, transfer, mortgage, pledge or otherwise
dispose of or deal in and with any of the shares of the capital stock, or any
voting trust certificates in respect of the shares of capital stock, scrip,
warrants, rights, bonds, debentures, notes, trust receipts, and other securities
obligations, choses in action and evidences of indebtedness or interest issued
or created by any corporations, syndicates, associations, firms, trusts or
persons, public or private, or by the government of the United States of
America, or by any foreign governmental, or by any state, territory, province,
municipality or other political subdivision or by any government agency, as
owner thereof to possess and exercise all the rights, powers and privileges or
ownership, including the right to execute consents and vote thereon, and to do
any and all acts and things necessary or advisable for the preservation,
protection, improvement and enhancement in value thereof.
To borrow or raise money for any of the purposes of the Corporation and
from time to time without limit as to amount, to draw, make, accept, endorse,
execute and issue promissory notes, drafts, bills of exchange, warrants, bonds,
debentures and other negotiable or non-negotiable instruments and evidences of
Indebtedness, and to secure the payment of any thereof and of the interest
thereon by mortgage upon or pledge, conveyance or assignment in trust of the
whole or any part of the property of the Corporation; whether at the time owned
or thereafter acquired, and to sell, pledge or otherwise dispose of such bonds
or other obligations of the Corporation for its corporate purposes.
To purchase, receive, take by grant, gift, devise, bequest or otherwise,
lease, or otherwise acquire own, hold, improve, employ, use and otherwise deal
in and with real or personal property or any interest therein, wherever
situated, and to sell, convey, lease, exchange, transfer or otherwise dispose
of, or mortgage or pledge, any or all of the Corporation's properly and assets.
or any interest therein, wherever situated.
In general, to possess and exercise all the powers and privileges granted
by the Oklahoma General Corporation Act, any other law of Oklahoma or this
Certificate of Incorporation together with any powers incidental thereto, so far
as such powers and privileges are necessary or convenient to conduct promotion
or attainment of the business or purposes of the Corporation.
The business and purposes specified in the foregoing clauses shall not be,
expected where otherwise expressesed, limited or restricted by reference to or
inference from the terms of any other clause in this certificate of
Incorporation, but the business and purposes specified in each of the foregoing
clauses of this Article Three shall be regarded as independent business and
purposes.
2
<Page>
ARTICLE FOUR
AUTHORIZED CAPITAL STOCK
This Corporation is authorized to issue only one (1) class of shares of
capital stock to be designated "Common Stock". The total number of share of
Common stock which this Corporation shall have authority to issue and the par
value of each share of Common Stock and the amount of the total authorized
Common Stock, are as follows:
<Table>
<Caption>
Total Number Par Value of Total Authorized
Of Shares Each Share Common Stock
50,000 $ 1.00 $ 50,000.00
</Table>
The Board of Directors of the Corporation shall have full authority, to the
extent permitted by law, to increase, decrease or otherwise adjust the capital
stock of the Corporation, to designate the classes or series thereof and to
determine whether all or any part of such stock shall have voting powers, full
or limited, or not voting powers, and to determine such designations and such
powers, preferences, relative, participating optional, or other special rights
qualifications, limitations or restrictions thereof, as the Board of Directors
shall from time to time determine in duly adopted resolutions.
At any time and from time to time when authorized by resolution of the
Board of Directors and without any action by its shareholders, the Corporation
may issue or sell any shares of its capital stock of any class or series,
whether out of the unissued shares thereof authorized by the Certificate of
Incorporation of the Corporation as originally filed or by amendment thereof or
out of shares of its capital stock acquired by it after the issue thereof, and
whether or not the shares thereof so issued or sold shall confer upon the
holders thereof the right to exchange or convert such shares for or into other
shares of capital stock of the Corporation of any class or classes or any series
thereof. When similarly authorized, but without any action by its shareholders,
the Corporation may issue or grant rights, warrants or options, in bearer or
registered form or such other form as the Board of Directors may determine, for
the purchase of shares of the capital stock of any class or series of the
Corporation within such period of time, or without limit as to time, to such
aggregate number of shares, as the Board of Directors may determine. Such
rights, warrants or options may be issued or granted separately or in connection
with the issue of any bonds, debentures, notes, obligations or other evidences
of indebtedness or shares of the capital stock of any class or series of the
Corporation and on such terms and conditions as the Board of Directors may
determine. In each case, the consideration to be received by the Corporation of
any such shares, rights, warrants, options, or other obligations or evidence of
indebtedness of the Corporation issued, granted or sold shall be such as shall
be fixed from time to time by resolution of the Board of Directors provided,
however, that no shares of capital stock of the Corporation shall be issued or
sold below par value, or if the shares do not have par value, not below their
stated value, as determined by the Board of Directors.
3
<Page>
ARTICLE FIVE
NUMBER OF DIRECTORS
The number of Directors of this Corporation shall be specified in the
Bylaws and such number may from time to time be increased or decreased under
the. Bylaws, or any amendment or change thereof. The number of Directors to be
elected at the first meeting of the Shareholders is one or more.
ARTICLE SIX
ELECTION OF DIRECTORS
Elections of directors need not be by written ballot, unless the Bylaws of
the Corporation shall so provide.
ARTICLE SEVEN
POWERS OF THE BOARD OF DIRECTORS
In furtherance and not in limitation of the powers conferred by statute,
the Board of Directors is expressly authorized:
(a) To adopt, amend or repeal the Bylaws of the Corporation.
(b) To authorize and cause to be executed or granted mortgages, security
interests and liens upon the real and personal property of the Corporation.
(c) To act apart out of any of the funds of the Corporation available for
dividends a reserve or reserves for any proper purpose and to abolish any such
reserve in the manner in which it was created.
(d) By a majority of the whole Board of Directors, to designate one or
more committees, each committee to consist of one or more of the directors of
the Corporation. The Board of Directors may designate one (1) or more directors
as alternate members of any committee who may replace any absent or disqualified
member at any meeting of the committee. Any such committee to the extent
provided in the resolution or in the Bylaws of the Corporation Shall have and
may exercise the powers of the Board of Directors in the management of the
business and affairs of the Corporation, and may authorize the seal of the
Corporation to be affixed to all papers which may require it provided, however,
the Bylaws may provide that in the absence or disqualification of any member of
such committee or committees, the member of members thereof present at any
meeting and not disqualified from voting, whether or not he she or they may
constitute a quorum, may unanimously appoint another member of the Board of
Directors to act at the meeting in the place of any such absent or disqualified
member.
(e) When and as authorized by the affirmative vote of the holders of the
majority of the stock issued and outstanding having voting power given at a
shareholders meeting duly called upon such notices as is required by law, or
when authorized by the written consent of the
4
<Page>
holders of a majority of the voting stock issued and outstanding, to sell, lease
or exchange substantially all of the property and assets of the Corporation,
including its goodwill and its corporate franchises, upon such terms and
conditions and for such consideration which may consist in whole or in part of
money or property including shares of stock in and/or other securities of, any
other corporation, as its Board of Directors shall deem expedient and for the
best interests of the Corporation.
ARTICLE EIGHT
DIRECTOR LIABILITY
No Director shall be personally liable to the Corporation or any
stockholder for monetary damages for breach of fiduciary duty by such Director
as a Director, except for any matter in respect of which such Director shall be
liable under Section 1031 of the Oklahoma General Corporation Act or any
amendment thereto or successor provision thereof or shall be liable by reason
that, in addition to any and all other requirements for such liability, he or
she (i) shall have breached his or her duty of loyalty to the Corporation or its
stockholders, (ii) in acting or in failing to act, shall not have acted in good
faith or shall have acted in a manner involving intentional misconduct or a
knowing violation of law or (iii) under Section 1053 of the Oklahoma General
Corporation Act, shall have allowed an unlawful payment of a dividend or
unlawful stock purchase or redemption (iv) shall have derived an improper
personal benefit from the transaction in respect of which such breach of
fiduciary duty occurred. Neither the amendment nor repeal of this Article Nine
shall eliminate or reduce the effect of this Article Nine in respect of any
matter, occurring, or any cause of action, suit or claim that, but for this
Article Nine would accrue or arise, prior to such amendment or repeal. If the
Oklahoma General Corporation Act is amended after approval by the stockholders
of this Article Nine to authorize corporate action further eliminating or
limiting the personal liability of Directors, then the liability of a Director
of the Corporation shall be eliminated or limited to the fullest extent
permitted by the Oklahoma General Corporation Act as so amended from time to
time.
ARTICLE NINE
RELATED PARTY TRANSACTIONS
To the extent permitted by law, no contract or transaction between the
Corporation and or one or more of its Directors or officers, or between the
Corporation and any other corporation, partnership, association or other
organization in which one or more of its directors or officers are directors or
officers or have a financial interest, shall be void or voidable solely for this
reason, or solely because the Directors or officers arc present at or
participate in the meeting of the board or committee thereof which authorized
the contract or transaction, or solely because the Directors or officers or
their votes are counted for such purpose.
ARTICLE TEN
INFORMAL REORGANIZATION
Whenever a compromise or arrangement is proposed between the Corporation
and its creditors or any class of them and/or between this Corporation and its
shareholders or any class of them any court of equitable jurisdiction within the
State of Oklahoma on the application in a
5
<Page>
summary way of the Corporation or of any creditor or shareholder thereof or on
the application of any receiver or receivers appointed for this Corporation
under the provisions of Section 1106 of the Oklahoma General Corporation Act or
on the application of trustees in dissolution or of any receiver or receivers
appointed for this Corporation under the provisions of Section 1100 of the
Oklahoma General Corporation Act, may order a meeting of the creditors or class
of creditors, and/or of the shareholders or class of shareholders of this
Corporation, as the case may be to be summoned in such manner as the court
directs. If a majority in number representing three-fourths (3/4) in value of
the creditors or class of creditors, and/or of the shareholders or class of
shareholders of the Corporation, as the case may be agree to any compromise
or arrangement and to any reorganization of the Corporation as a consequence of
such compromise or arrangement, the compromise or arrangement and the
reorganization, if sanctioned by the court to which the application has been
made, shall be binding on all the creditors or class of creditors, and/or on all
the shareholders or class of shareholders, of the Corporation, as the case may
be, and also on the Corporation.
ARTICLE ELEVEN
AMENDMENT OF CERTIFICATE OF INCORPORATION
The Corporation reserves the right to amend, alter, change or repeal any
provision contained in this Certificate of Incorporation, in the manner now or
hereinafter prescribed by law and all rights conferred upon the shareholders
herein are granted subject to this reservation; provided however, that no
amendment to this Certificate of Incorporation shall be made which imposes
personal liability for the debts, actions or otherwise of the Corporation or its
shareholders without the consent of the holders of all of the capital stock of
the Corporation, whether or not they may be otherwise entitled to vote.
This Amended Certificate of Incorporation was duly adopted in accordance
with Section 1077 of the Act after being proposed by the sole director and
adopted by the sole shareholder in the manner and by the vote prescribed in
Section 1077 of the Act.
IN WITNESS WHEREOF, I have hereunto set my signature at Oklahoma City, OK
on this 5th day of January, 2001.
/s/ Tommy L. Hewett
--------------------------------
Tommy L. Hewett, Chairman
6
<Page>
STATE OF OKLAHOMA )
)
COUNTY OF OKLAHOMA )
Before me, the undersigned, a Notary Public, in and for said State on this
8th day of January, 2001. personally appeared Tommy L. Hewett. M.D., to me known
to be the identical person who executed the within and foregoing Certificate of
Incorporation, and acknowledged to me that he executed the same as his free and
voluntary act and deed for the uses and purposes therein set forth.
Under my hand and official seal the day and year last above written.
MY COMMISSION EXPIRES:
10-14-01 [ILLEGIBLE]
---------------------------
(SEAL) Notary Public
[ILLEGIBLE]
7