Anatomic Abstracts

January 2004

• Negative sentinel lymph nodes in melanoma patients with regional recurrence
• Criteria used to identify endometrioid tumors of low malignant potential
• Clinical impact of expert pathologic review on lymphoma management

Negative sentinel lymph nodes in melanoma patients with regional recurrence

A sentinel lymph node that is melanoma-negative by pathologic examination implies absence of melanoma metastasis to that regional lymph node field. A small proportion of patients, however, develop regional node field recurrence after a negative SLN biopsy. In this study, the authors reviewed the histopathology of negative SLNs from such patients to determine whether occult melanoma cells were present in the SLNs as well as to characterize the pathologic features of false-negative SLNs and provide recommendations for the histopathologic examination of these specimens. Of 1,152 patients who had undergone SLN biopsy for primary melanomas at the Sydney Melanoma Unit, 976 were diagnosed with negative SLNs by initial pathologic examination (using two hematoxylin and eosin-stained sections and two immunostained sections for S-100 protein and HMB45), and followup was available for 957. Of these, 26 (2.7 percent) developed regional lymph node recurrence during a median followup of 35.7 months. For 22 of these cases, the original slides and tissue blocks were available for re-examination. The original slides of each block were reviewed. Multiple further sections were cut from each block and stained with hematoxylin and eosin for S-100, HMB45, and Melan-A. Deposits of occult melanoma cells were detected in seven of the 22 cases (31.8 percent). In five of the seven cases (71 percent), deposits of melanoma cells were present only in the recut sections. No significant differences were noted in clinical and pathologic variables for those patients in whom occult melanoma cells were found by pathologic re-examination of their SLNs, compared with those in whom no melanoma cells were detected. Detecting melanoma cell deposits in only seven of 22 false-negative SLNs suggests that mechanisms other than failure of histopathologic examination may contribute to the failure of the SLN biopsy technique in some patients. The failure rate for melanoma detection in SLNs by the pathologic schema described was less than one percent (seven of 957 patients). Performing more intensive histopathologic examination of SLNs on a routine basis is difficult to justify from a cost-benefit perspective. The authors, therefore, recommended examining two hematoxylin and eosin-stained sections and two immunostained sections (for S-100 and HMB45) routinely on SLNs from melanoma patients.

Li LX, Scolyer RA, Ka VS, et al. Pathologic review of negative sentinel lymph nodes in melanoma patients with regional recurrence; a clinicopathologic study of 1152 patients undergoing sentinel lymph node biopsy. Am J Surg Pathol. 2003;27: 1197-1202.

Reprints: Dr. Richard Scolyer, Dept. of Anatomical Pathology, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia; richard.scolyer@email.cs.nsw.gov.au

Criteria used to identify endometrioid tumors of low malignant potential

The application of morphologic criteria used to separate ovarian endometrioid tumor of low malignant potential (ETLMP) from well-differentiated endometrioid carcinoma can be confusing. The authors conducted a study in which the criteria used helped to identify ETLMP, none of which recurred on followup of more than six months (0/10), as compared to the well-differentiated endometrioid carcinomas, of which 20 percent (3/15) recurred within the same time interval. The criteria used to identify ETLMP included absence of destructive stromal invasion (DSI), glandular confluence, or stromal disappearance. Intracystic villoglandular/papillary growth or cribriform pattern in the absence of DSI, glandular confluence, or stromal disappearance was also classified as ETLMP. ETLMP was distinguished from benign endometrioid tumors by the presence of cytologic atypia (nuclear grade one or higher). ETLMP with grade three nuclei were termed intraepithelial carcinoma, and those with stromal invasion of 10 mm² or less were termed microinvasive tumors. None of these features influenced the prognosis for ETLMP.

Roth LM, Emerson RE, Ulbright TM. Ovarian endometrioid tumors of low malignant potential: a clinicopathologic study of 30 cases with comparison to well-differentiated endometrioid adenocarcinoma. Am J Surg Pathol. 2003;27:1253–1259.

Reprints: Dr. Lawrence M. Roth, Dept. of Pathology, Indiana University Hospital, Room 3465, 550 N. University Blvd., Indianapolis, IN 46202-5280; lroth@iupui.edu

Clinical impact of expert pathologic review on lymphoma management

The All Wales Lymphoma Panel is a central expert pathological review service that reviews all primary lymphoma diagnoses made by district general hospital pathologists. It also functions as a primary diagnostic service for cases in which the diagnosis is not known. In a previous report, the group documented a 20 percent discordance rate between initial and reviewed diagnoses over the two-year period following its inception. The current study attempts to determine whether changes in diagnosis affect patient management. Between January 1998 and August 2000, 125 of 745 (17 percent) cases received for review by the All Wales Lymphoma Panel had a consequent change in diagnosis. Changes included reclassification from one non-Hodgkin lymphoma category to another, revision of NHL to Hodgkin lymphoma or vice versa, and, in 42 cases (42 percent), reclassification from reactive lymphadenopathy to malignant lymphoma or vice versa. Complete case notes were recovered in 99 cases (79 percent). For these cases, a hypothetical management plan was generated based on the diagnosis submitted, clinical protocols, and patient clinical information, including history, presentation, and IPI score. This was compared with the treatment the patients received after the revised diagnosis. Forty-six of the 99 cases (46 percent) had a change in management as a result of expert review. Changes included treatment to no treatment, no treatment to treatment, and modification of treatment regimen. The authors concluded that expert pathologic review is important for accurate diagnosis and directly impacts patient management.

Lester JF, Dojcinov SD, Attanoos RL, et al. The clinical impact of expert pathological review on lymphoma management: a regional experience. Br J Haematol. 2003;123:463-468.

Correspondence: Dr. Jason Lester, Velindre Hospital NHS Trust, Whitechurch, Cardiff CF14 2TL, United Kingdom; jason.lester@velindre-tr.wales.nhs.uk