MOHS MICROGRAPHIC SURGERY: A HISTORICAL PERSPECTIVE

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MOHS MICROGRAPHIC SURGERY A HISTORICAL
PERSPECTIVE Patricia Ting, BSc, Anatoli Freiman,
MD Division of Dermatology, McGill University
Health Centre, Montreal, Canada
ABSTRACT In the early 1930s, as a medical student
at the University of Wisconsin, Fredric E. Mohs
pioneered the idea of microscopically-controlled
removal of cutaneous tumours. With its ability to
systematically examine 100 of lesion margins,
Mohs Micrographic Surgery (MMS) allows for
maximal sparing of normal tissues and provides
excellent cosmetic results. Whereas today, it is
considered one of the greatest contributions to
the field of dermatologic surgery, the widespread
acceptance of the technique took over 50 years.
We review the key historical events and people
involved in the development of MMS.

• INK DYES
• Mohs refined his technique by color-coding the
  specimen edges with
• Red (merbromin)
• Blue (laundry dye)
• Black (India ink)
• The addition of ink dyes provided a precise
  reference map of the tumour to be drawn and
  juxtaposed upon the corresponding surgical wound
  bed.

Dr. Fredric E. Mohs (1910-2000)

• THE BEGINNINGS
• In the early 1930s, as a young medical
  student at the University of Wisconsin, Frederic
  E. Mohs worked as an
• assistant in a cancer research laboratory,
  investigating the effect of various irritants on
  implanted cancers in rats.
• Mohs observed that injections of 20 zinc
  chloride effectively and accurately penetrated
  the tissues without
• systemic toxicity. Furthermore, the chemical
  was also safe to handle, as it did not diffuse
  into the keratin layer of
• the skin, unless a keratolytic, such as
  dichloroacetic acid, was previously applied.
  Most importantly, this zinc
• preparation maintained the histologic
  architecture of tissues.
• Mohs subsequently proposed the concept of
  chemical fixation followed by surgical excision
  of tumors with
• microscopic examination of tumor margins.
  And thus, the concept of micrographic
  chemosurgery was born.
• In 1936, after formal training as a general
  surgeon, Dr. Mohs began treating patients with
  cutaneous malignancies in
• the dermatology clinic at the Wisconsin
  General Hospital. An elderly pharmacist at the
  drug store supplied him with
• the ingredients required for the topical
  fixative paste containing stibinite (an antimony
  ore, which served as a
• granular matrix) and sanguinaria canadenis
  (a binder for the saturated solution of zinc
  chloride).

• FRESH TISSUE TECHNIQUE
• In 1951, Dr. Ray Allington suggested that
  dichloroacetic acid could be used for hemostatis
  after the debulking
• procedure. A monumental change in Mohs fixed
  tissue technique serendipitously occurred in 1953
  during the filming of
• an instructional documentary demonstrating
  Dr. Allingtons suggestion on a multistage
  removal of an eyelid basal cell
• carcinoma. Due to the time constraints of
  the filming session, Mohs injected the residual
  tumour area with local
• anesthetic and omitted the second round of
  the zinc chloride fixation.
• It was soon realized that the resolution of
  tumor margins was not significantly impeded
  without fixation. This
• became known as the fresh-tissue technique,
  which was also illustrated in Mohs chapter in
  the 1st edition of
• Epsteins Skin Surgery in 1956.
• With this procedural modification, patients
  experienced significantly less pain and
  morbidity. Because of the
• absence of tissue inflammation and
  sloughing, which were previously observed
  secondary to zinc chloride application,
• more tissue could be conserved and
  reconstruction of the wound bed could now take
  place on the same day as the
• excision.

1st Meeting of the American College of
Chemosurgery in 1967 (Chicago). Front row
center Dr. Fredric E. Mohs.
Source Brodland et al. 2000

• MILESTONES IN THE DEVELOPMENT OF MOHS
  MICROGRAPHIC SURGERY
• 1933 Fredric Mohs original concept of
  chemosurgery for cutaneous neoplasms.
• 1936 Dr. Mohs begins using his technique at the
  Wisconsin General Hospital.
• Dr. Mohs reports 440 patients successfully
  treated with chemosurgery.
• 1946 Mohs technique caught the attention of
  dermatologists at the American Academy of
  Dermatology meeting in Chicago.
• The fresh tissue technique used for the first
  time during the filming of an instructional
  documentary on Mohs technique for the removal of
  eyelid tumours.
• 1956 Mohs technique appears in the 1st edition of
  Epsteins Skin Surgery.
• Establishment of the first 1-year fellowship in
  Mohs surgery at NYU Medical Centre by Perry
  Robbins.
• 1st American College of Chemosurgery meeting with
  23 attendees.
• 1969 Dr. Mohs presents a 100 cure rate for
  eyelid tumours using the fresh tissue technique
  at the 3rd American College of Chemosurgery
  meeting.
• 1970 Dr. Theodore Tromovitch reports successful
  results with the fresh tissue technique at the
  4th American College of Chemosurgery meeting.
• Dr. Daniel Jones, a trainee of Dr. Mohs, coins
  the term micrographic surgery."
• 1st issue of the Journal of Dermatologic Surgery
  and Oncology published.
• Textbook of Chemosurgery Microscopically
  Controlled Surgery for Skin Cancer written by Dr.
  Mohs.
• Minimum 1-year fellowships regulated by the
  American College of Chemosurgery.
• American College of Chemosurgery renamed to
  American College of Mohs Micrographic Surgery and
  Cutaneous Oncology (ACMMSCO).
• 1991 Establishment of the American Board of Mohs
  Micrographic Surgery and Cutaneous Oncology.
• Adapted from Brodland et al. 2000

ORIGINAL PROCEDURE FOR MOHS CHEMOSURGERY FIXED
TISSUE TECHNIQUE (1936 1948) Step 1 Injection
of local anesthetic (Figure 1) . Step 2 Removal
and curettage of superficial tumour (Figure
2). Step 3 Application of dichloracetic acid
(Figure 3) and in-situ zinc
chloride fixative paste for 12 to 24 hours
(Figure 4 5). Step 4 Surgical excision of
tumour in saucer-like horizontal
sections (Figure 6). Step 5 Microscopic
examination of frozen sections.
Figure 6. Diagrammatic representation of
horizontal sections used in Mohs technique.

• ACCEPTANCE OF MOHS MICROGRAPHIC TECHNIQUE
• By the mid-1960s, Mohs technique gained wide
  acceptance, eventually leading to the
  establishment of American
• College of Chemotherapy in 1967.
• At the annual meeting in 1970, Dr. Theodore
  Tromovitch, who had been using the fresh tissue
  technique since the
• 1960s, presented a case series of 75
  patients treated for cutaneous carcinomas and
  reported equally high cure
• rates with this new technique, which also
  proved that the real reason for the success of
  the fresh-tissue Mohs
• surgery was not the chemical fixation of the
  tissue, but the microscopic control.
• In 1986, the American College of Chemosurgery
  was renamed the American College of Mohs
  Micrographic Surgery
• and Cutaneous Oncology (ACMMSCO) and minimum
  one-year fellowships in Mohs Micrographic Surgery
  were
• officially regulated via this organization.
• The Mohs surgery fellowship requires
  specialized training in a composite of skills
  including dermatopathology and
• reconstructive surgery.

Source Mohs, FE. Chemosurgery Microscopically
Controlled Surgery for Skin Cancer (1978).

• CONCLUSIONS
• Winning general acceptance takes much patience,
  said Dr. Fredric Mohs.
• The development and widespread acceptance of
  Mohs micrographic surgery has taken over 50
  years.
• Although the original concept of micrographic
  surgery began in the early 1930s, 12 years
  elapsed before the
• development of the original fresh tissue
  technique (1936 to 1948), and its use for
  cutaneous carcinomas did not
• begin until 17 years later (1953 to 1970).
• With its ability to systematically examine
  100 of tumour margins, Mohs Micrographic Surgery
  allows for maximal
• sparing of normal tissues and provides
  excellent cosmetic results.
• Today, it is considered one of the greatest
  contributions to the field of dermatologic
  surgery.

INITIAL REJECTION OF MOHS FIXED TISSUE
TECHNIQUE Between the 1930 1950s, Mohs
pioneering surgical concept for the treatment of
cutaneous malignancies was not well accepted by
the medical community for several reasons
1. Patients complained of extreme pain due to the
caustic effects of zinc chloride fixative, which
induced edema and tissue necrosis 2. Local
inflammation made it difficult to interpret
tumour histopathology 3. Microscopic
examination of the margins and repeating process
for incompletely excised tumor was very labor
intensive 4. Increased infection rates due to
delayed surgical reconstruction and closure of
wound bed/defect 5. Belief that cutting
through the tumour would promote local seeding of
tumour cells and metastatic spread Therefore,
surgeons at the time preferred to use
conventional wide surgical margins.

• For residual neoplastic tissue, the process
  of fixation, surgical
• excision and microscopic examination were
  repeated until the margins
• cleared.
• The defect was allowed to heal by secondary
  intention as the
• fixative sloughed over the course of 7 to
  10 days (Figure 7 8).
• If required, skin grafts were performed
  after this time period.
• Mohs technique allowed for histological
  examination of entire base and
• margins of the defect,

ACKNOWLEDGEMENTS Special thanks to Dr. Lawrence
Warshawski, Dr. Dan Issen Dr. David Zloty
(Vancouver, BC) for the clinical photos and to
Dr. Channy Y. Muhn (Burlington, Ontario) for the
inspiration.
Source Mohs, FE. Chemosurgery Microscopically
Controlled Surgery for Skin Cancer (1978).