College of American Pathologists
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Melanoma claims: from overreaction to oversight

August 2002
Alvin Ring, MD

Marva West Tan, RN, ARM

Following are analyses of closed melanoma claims managed by The St. Paul and MMI Companies Inc., St. Paul, Minn. Some facts may have been changed in the following cases to protect confidentiality.

Case 1 - Misdiagnosis of malignant melanoma

Allegation: Misdiagnosis of atypical Spitz nevus of right buttock as malignant melanoma and fear of death for four-and-a-half years.

Defendants: Pathologist and pathology laboratory.

Facts of case: A 37-year-old woman had a mole removed from her right buttock in September 1991. The mole was sent to a pathology laboratory for analysis. Pathologist X’s report stated: "Malignant melanoma, superficial spreading pattern, largely in situ with focal invasion abutting on the reticular dermis (Clark’s level III). The lesion measures 0.5 mm in thickness and is incompletely excised, right buttock." The pathologist noted that a limited re-excision (0.5 to 1.0 mm) is indicated for the lesion.

Three other pathologists in the practice concurred in the diagnosis and their names appear on the report.

For approximately four-and-a-half years following the melanoma diagnosis, the patient became obsessed with dying and believed the condition would cause her demise. She had four or five additional moles removed, became depressed, was unable to continue her usual activities, and, consequently, gained weight.

In spring 1996, the patient changed health insurance and her new physicians re-analyzed her condition. They reviewed the original specimen from the September 1991 analysis. While the outside pathologists’ letters or reports are not contained in the claims file, a summary indicated that one plaintiff pathologist expert diagnosed the original lesion as atypical Spitz nevus and another pathologist expert diagnosed the lesion as atypical Spitz nevus and recommended wide excision.

Legal action: Shortly after receiving this new opinion regarding her diagnosis, the patient requested mediation by the state compensation fund. (Mediation is an alternative dispute resolution mechanism whereby a neutral third party facilitates a mutually acceptable agreement. The process, the composition of the mediation panel, and whether or not the findings are binding vary by state.) The mediation was scheduled for approximately two months later. The mediation panel was chaired by an attorney and consisted of a neutral pathologist, a layperson, the patient or claimant and her attorney, and the respondents or defendants, which were Pathologist X and the pathology laboratory and its attorneys and representatives of its insurers.

The claimant’s allegations were presented as detailed above. The defense’s position was that the consensus of the pathologists who had seen the slide of the specimen was that the initial reading was correct and Pathologist X’s report is within the standard of care. Even the claimant’s expert noted that the diagnosis is an extremely close call. Moreover, the defense noted that if the lesion is atypical Spitz nevus, the claimant received proper treatment. The claimant’s anxiety, while understandable, is an over-reaction, according to the defense. Medical records indicate that the claimant’s physicians informed her that her prognosis was very good.

The patient countered that she had not been informed she had a 98 percent chance of survival.

After closed discussion, the mediation panel supported the defense. No suit was filed, and the statute of limitations expired on this case. Losses were limited to defense costs.

Clinical issues and standard of care: This case is overshadowed by social and patient-centered issues, mainly the patient’s reaction to a diagnosis of malignancy, which was exacerbated by her knowledge of two acquaintances who had died of melanoma. Nevertheless, issues surround the diagnosis and the interaction of the pathologists with the clinicians and the clinicians with the patient, as well as the informed consent.

Many pathologists would agree that Pathologist X handled this case appropriately. They would also agree with his comment that the lesion was incompletely excised and his suggestion that re-excision was indicated. (Although stating in the report that a 0.5-cm to 1-cm re-excision was indicated may be encroaching on the clinicians’ prerogatives.) Most pathologists also would have described the microscopic findings leading to a diagnosis of malignant melanoma and, if the lesion was unusual, the differential diagnosis. The report did not contain notations regarding discussions with the surgeon.

A positive feature of the report is a statement that the diagnosis was made in consultation with three other pathologists in the group. Because there is no discussion of differential diagnosis or difficulty in making a diagnosis, it is assumed that the four pathologists were confident the diagnosis was correct and did not consider other alternatives, which might have led to outside consultation by an expert in the field. The fact that one expert pathologist who subsequently reviewed the case called the lesion atypical Spitz nevus but suggested additional wide excision demonstrates that even expert dermatopathologists sometimes have difficulty with these lesions.

A November 1996 editorial in Human Pathology, titled "Discordance among expert pathologists in the diagnosis of melanocytic neoplasms," described a study in which a panel of 11 expert pathologists was convened and reviewed 37 classic melanocytic neoplasms. The experts were in agreement about whether the neoplasms were benign or malignant in only 30 percent of the cases.1 A 1999 study reported similar marked disagreement among experts in the differential diagnosis of melanoma and Spitz nevi.2 Recurrent Spitz nevi are even more problematic since the original symmetry has been lost.

One series reported that 6.5 percent of all melanomas referred to a consulting service were Spitz nevi, and that Spitz nevi represented the majority of pathologically misdiagnosed melanomas. This study stressed that greater clinical--pathologic communication may reduce the frequency of diagnostic errors.3

Pathologists faced with difficult melanocytic lesions obviously should seek expert advice if for no other reason than to show in a court of law that such advice was sought. Discussions with an expert also provide an educational opportunity. Disclaimers should appear in the report if the lesion is a shave biopsy or incompletely excised. From a practical viewpoint, re-excision may be reasonable, even in a well-characterized Spitz nevus, because if it were to recur in a previously biopsied area, the distortion and treatment-related atypia might hinder diagnosis. Even sentinel lymph node excision has been proposed selectively since metastasis to the sentinel lymph node would confirm the diagnosis of malignant melanoma.4

Patient education: Patients may have unrealistic expectations that the diagnostic process is easy or straightforward in all situations. Helping patients develop realistic expectations about diagnosis and treatment is important. The trust created during these discussions may set the stage for better patient-physician communication when unexpected outcomes occur. It is not clear in this case why the patient’s initial contact with Pathologist X was an attorney’s request for mediation rather than a personal request to discuss the differences in the diagnoses.

Patients with cancer diagnoses obviously want to understand their prognosis, treatment options, medications, and after-care. They often need to have information repeated and to have questions answered. Physicians, however, do not need to provide all the information themselves. Involving other members of the health care team and using preprinted materials or referring interested patients to online cancer information sources are options.

CAP TODAY consulted with two dermatopathologists about this issue. Following is their opinion: We believe pathologists seldom have access to patients and typically do not want to interfere with the -clinician-patient relationship. Pathologists need to protect themselves from legal action by using lawyer-approved disclaimers and hedges and by implementing procedures to track clinical information and to ensure accurate record-keeping.

We recommend that regular Spitz nevi in adults be excised. One of the dermatopathologist’s labs uses the disclaimer "although controversial, complete excision with a margin of normal skin is recommended." The lab uses numerous disclaimers, such as, "If this specimen represents just part of a significantly larger lesion, the findings may not be representative of the entire lesion." We don’t usually diagnose a straight out Spitz nevus if the lesion is a shave specimen in an adult, and we will usually hedge to force the clinician to take it off.

1.  Ackerman AB. Discordance among expert pathologists in the diagnosis of melanocytic neoplasms. Ed. Hum Pathol. 1996;27:1115-1116.

2.  Barnhill RL, Argenyi ZB, et al. Atypical Spitz nevi/tumors: lack of consensus for diagnosis, discrimination from melanoma, and prediction of outcome. Hum Pathol. 1999;30(5):513-520.
3.  Orchard DC, Dowling JP, Kelly JW. Spitz nevi misdiagnosed histologically as melanoma. Australia Journal. 1997; 38(1):12-14.

4.  Lohmann CM, Coit DG, et al. Sentinel node biopsy in patients with diagnostically controversial spitzoid melancytic tumor. Am J Surg Pathol. 2002; 26: 47-55.

Case 2 - Misdiagnosis of malignant melanoma

Allegation: Desmoplastic melanoma misdiagnosed as nodular fasciitis.

Defendants: Pathologist No. 1, Pathology Laboratory No. 1, Pathologist No. 2, Pathology Laboratory No. 2, and plastic surgeon.

Facts of case: The patient, a 31-year-old woman, had a lesion removed from her left anterior chest wall by her family physician on March 12, 1993. The specimen was sent to laboratory No. 1. On March 14, 1993, Pathologist No. 1 issued a report of "skin biopsy, left anterior chest, actinic lentigo." Following is the sequence of events:

  • The lesion recurred and the patient was referred to a plastic surgeon that treated her from August 1994 to May 1996. The surgeon apparently never received nor reviewed the family practitioner’s medical records or the March 1993 pathology report.
  • August 24, 1995 The plastic surgeon performed an "excision of recurrent keloid scar of the left upper anterior chest in lateral infra clavicular area." The specimen was sent to lab No. 2.
  • August 29,1995 Pathologist No. 2 issued a report of "proliferating fibroblasts and chronic inflammatory cells most consistent with nodular fasciitis."
  • December 28, 1995 The plastic surgeon performed another "excision of recurrent nodular fasciitis of left upper anterior lateral chest and left lateral clavicular area" and again sent the specimen to lab No. 2.
  • December 29, 1995 Pathologist No. 2’s report noted "spindle cell proliferation with chronic inflammatory infiltrate consistent with nodular fasciitis, and focal foreign body-type giant cells and suture material consistent with previous excision." At the time of the August 1995 and December 1995 reports, Pathologist No. 2 was not aware of Pathologist No. 1’s 1993 report.
  • April 1996 Pathologist No. 2 was informed by the plastic surgeon that the patient had a large axillary mass and apparently learned of the 1993 pathology report. Pathologist No. 2 then requested a S-100 stain on the 1995 specimens and contacted lab No. 1 for slides, paraffin block, and a faxed copy of the 1993 pathology report. The S-100 stain was strongly positive, and Pathologist No. 2 felt that Pathologist No. 1’s 1993 report indicated a "previous melanocytic lesion."
  • May 10, 1996 Pathologist No. 2 issued amended pathology reports from August 1995 and December 1995 as "desmoplastic melanoma, Clark’s level IV."
  • May 23, 1996 The patient underwent a wide excision of skin and subcutaneous tissue from the lateral chest wall. The tissue demonstrated residual desmoplastic melanoma as well as metastasis to one of 21 axillary lymph nodes.
  • June 28, 1996 The patient had an axillary node dissection that showed reactive fibrosis (doubt recurrence of desmoplastic mela-noma) and foreign body giant cell reaction. An oncologist treated the patient with interferon.
  • February 6, 1997 The patient underwent a radical neck dissection for recurrence of malignant melanoma. Pathology showed metastatic desmoplastic malignant melanoma with 21 negative cervical lymph nodes.
  • March 18, 1997 A bone biopsy of the right femur showed fragments of marrow tissue with fragments of desmoplastic malignant melanoma, metastatic.

Legal action: In May 1997, the two pathologists and the two pathology laboratories received notice from the plaintiff’s attorney of intent to file a medical malpractice action. The plastic surgeon subsequently was added to the action. The plaintiff’s allegations included misdiagnosis of cancer and delay of diagnosis leading to a loss of chance of cure. The plaintiff’s pathology expert stated that the pathologists and pathology laboratories breach-ed the standard of care, thereby failing to correctly diagnose cancer and failing to correctly report cancer to the treating physician.

The defense expert pathologist for Pathologist No. 2 said the latter did not deviate from the standard of care and that the outcome of the disease was already determined by 1995. (The latter element of that opinion speaks to the matter of causation. The elements of a medical malpractice tort include not only the requirement that the standard of care must be breached but also that the breach must have caused the plaintiff’s damages.) A different insurer and a different law firm represented Pathologist No. 1, and expert witness information is not available regarding that clinician’s practice. The plaintiff’s deposition was videotaped to preserve testimony following court approval. (Videotaped depositions are sometimes done when patients are terminal or otherwise may not be available for a court appearance.) The plaintiff made a sympathetic presentation on deposition.

Multiple defendants represented by different insurers and law firms that did not agree on an approach to the defense complicated this case. Finger-pointing among defendants regarding relevant clinical information not being shared further weakened the defense’s case. This claim was settled in February 1998 in the middle ranges on behalf of all defendants.*

Clinical issues and standard of care: This case exemplifies several issues in diagnostic error, including failure to consider a diagnosis, pursuing a wrong hypothesis or narrowed diagnostic path, failure to follow through, and bad information. In 1993, Pathologist No. 1 reported "actinic lentigo." Upon recurrence, Pathologist No. 2 issued a report of "proliferating fibroblasts and chronic inflammatory cells, most consistent with nodular fasciitis." In December 1995, another recurrence led to the repeat diagnosis of nodular fasciitis.

It wasn’t until May 1996, upon learning of a large axillary mass, that Pathologist No. 2 requested an S-100 stain. The stain was strongly positive and the pathologist issued an amended pathology report stating "desmoplastic mela-noma, Clark’s level IV." In other words, neither Pathologist No. 1 nor No. 2 considered the diagnosis of desmoplastic melanoma until metastasis had developed. Having pursued the hypothesis that the lesion was a proliferative fibroblastic lesion, Pathologist No. 2 offered the diagnosis of nodular fasciitis and the recurrence as excision of recurring nodular fasciitis. This diagnosis was apparently influenced by the plastic surgeon’s clinical diagnosis of recurrent keloid scar. The plastic surgeon and pathologist had not reviewed the medical records and pathology report from March 1993.

Desmoplastic melanomas, especially in their earlier phases, present significant diagnostic difficulties for the pathologist. They tend to be amelanotic, and atypia may be so minimal that distinctions between tumor cells and activated fibro-blasts may not be apparent. Superficial biopsies may be misdiagnosed as benign lentiginous lesions, or if the melanocytic component is overlooked, as fibromatosis or fibrohistiocytic tumor.1,2 Alternatively, the spindle cell component may suggest a Spitz nevus, cellular scar, or nerve sheath tumor. Because desmoplastic melanomas are rare compared to common fibrohistiocytic lesions, the diagnosis may not be considered, and immunostains for S-100 protein may not be performed. The lymphoid reaction, which may be a tip-off, tends to be at the advancing edge of the lesion and may not be seen in superficial biopsies, or it

may be misdiagnosed as nonspecific inflammation in a deeper biopsy.3

The first step in considering the diagnosis of desmoplastic melanoma is a careful search for lentiginous and junctional components, especially in actinically damaged skin.2-4 A greater degree of atypia in the deep dermal and subcutaneous components or single files of atypical spindle cells among sclerotic collagen bundles should be a clue. Unfortunately, clinical information or diagnoses, such as scar or hypertrophic scar, supplied by dermatologists or surgeons in these frequently amelanotic lesions are not helpful or may even be misleading.

Because most desmoplastic mela-nomas are variants of lentigo maligna melanoma, history of a lentiginous lesion with recurrence is helpful, especially in sites of actinic exposure after the age of 40, though not exclusively. Asymmetry may help differentiate the lesion from Spitz nevus. Neurotropic growth is another helpful common occurrence in desmoplastic melanomas,2-4 as is invasion of deep vascular channels. Diagnoses of recurrent scars and fasciitis should be cause for concern.

The HMB-45 stain, which many pathologists use in the diagnosis of melanoma, usually will be negative. The S-100 immunostains, however, are generally positive.

Issues in diagnostic error: Human factors research indicates that there are recurrent mechanisms in diagnostic error, including those mentioned previously, which are failure to consider a diagnosis, pursuing a wrong hypothesis or narrow diagnostic path, failure to follow through, and bad information.

The failure to communicate relevant clinical information was a quality weakness and a liability in this case. Patients generally have multiple clinicians involved in their care. Better systems should be implemented for sharing clinical information among a patient’s caregivers. Pathologists should have a system to pursue additional clinical information when they have questions about the limited data supplied in the request for specimen analysis.

CAP TODAY’s two consultant dermatopathologists offer another opinion: We do not practice with the assumption that the clinician will provide accurate, or any, clinical information. In some cases, a doctor may not even record why a procedure is being performed.

One of the dermatopathologist’s labs requests a previous biopsy report in all cases of scar. The clinician’s office may deny a previous history. However, you will have a record that you made such a request.

1.  Longacre TA, Egbert BM, Rouse RV. Desmoplastic and spindle-cell malignant melanoma. An immunohistochemical study. Am J Surg Pathol. 1996;20(12):1489-1500.

2.  Egbert B, Kempson R, Sagebiel R. Desmoplastic malignant melanoma. A clinicohistopathologic study of 25 cases. Cancer. 1988;62(9):2033-2041.

3.  Anstey A, McKee P, Jones EW. Desmoplastic malignant melanoma: a clinicopathological study of 25 cases. Br J Dermatol. 1993;129(4):359-371.

4.  Jain S, Allen PW. Desmoplastic malignant melanoma and its variants. A study of 45 cases. Am J Surg Pathol. 1989;13(5):358-373.

Susan Tannenbaum, MD, chair of the CAP Insurance Committee, concludes: Malignant melanoma is a serious and controversial subject. Experts sometimes differ on the best way to protect against liability in such cases. The experts do, however, agree that one must be diligent in documenting that every effort was made to render the proper diagnosis. This often includes seeking and documenting an expert second opinion.

* For purposes of this article, middle ranges are from $100,000 to $500,000.

Dr. Ring is medical director of laboratories, Silver Cross Hospital, Joliet, Ill., and clinical professor of pathology, University of Illinois College of Medicine. He is a member of the CAP Insurance Committee. Tan is a former senior communicator, health care risk services, The St. Paul.