Microscopic Examination of Findings Encountered during Cadaver Dissection: Malignant, Benign or Anatomic Variation?

Research Article

Austin J Anat. 2017; 4(3): 1070.

Microscopic Examination of Findings Encountered during Cadaver Dissection: Malignant, Benign or Anatomic Variation?

Cicioni M, Ly V, Zhang G and Fenderson BA*

Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, USA

*Corresponding author: Bruce A. Fenderson, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, 1020 Locust Street, Room 263 Jefferson Alumni Hall, Philadelphia, PA 19107. USA

Received: January 19, 2017; Accepted: March 20, 2017; Published: March 29, 2017

Abstract

Pathologic findings encountered during cadaver dissection provide an opportunity for integrating the preclinical basic sciences and encouraging critical thinking. The objective of this study was to determine whether it is possible to make a pathologic diagnosis of an unknown mass from an embalmed cadaver. Diagnoses would have to be based solely on gross and microscopic appearance of tissue, without clinical histories of the cadaveric donors. The tissue samples we removed from each mass were surprisingly well preserved and showed minimal autolysis. Indeed, some of the histological detail was as clear as may be found in any textbook. We were able to obtain a pathologic diagnosis for 6 cases that illustrate complications of malignant neoplasms arising in the colon, breast, ovary, and kidney. Our results emphasize the importance of integrating gross and microscopic anatomy with pathology to facilitate a comprehensive understanding of disease. This histopathology independent learning project could become an integral part of dissection-based anatomy courses, and stimulate students to become more inquisitive when they see something out of the ordinary in their cadaver.

Keywords: Medical education; Cadaver dissection; Gross anatomy; Pathology; Ovarian cancer; Breast cancer; Metastatic cancer

Abbreviations

H&E: Hematoxylin and Eosin

Introduction

Pathologic findings, anatomic variations, and evidence of past surgical procedures are frequently encountered during cadaver dissection [1-4]. These unexpected findings provide a valuable opportunity for active learning that integrates the preclinical basic sciences and stimulates the development of critical thinking skills [5]. To promote independent learning, students at Thomas Jefferson University are encouraged to investigate unexpected findings in their cadavers during dissection. However, upon gross inspection, it may remain unclear whether these discoveries are pathologic or the result of variability in anatomic development.

Previously, we described two cases that provided excellent opportunities for integrating anatomy with pathology and clinical medicine [4]. The first case was a massive ovarian tumor that displaced the urinary bladder and uterus, and compressed the ureters and rectum. The second case appeared to be breast cancer with widespread metastases. Students discussed clinical complications of these cases and reviewed clinicopathologic findings that differentiate benign from malignant neoplasms. Despite the interest that these cases generated, in terms of class discussion and independent study, gross inspection of the tumors did not permit us to establish a pathologic diagnosis.

The objective of this study, a medical student honors project, was to determine whether it is possible to make a pathologic diagnosis of an unknown mass from a cadaver, in which the preservation of organs and tissues following routine embalming, dissection, and storage was unknown. Without good preservation of cellular and nuclear morphology, it is difficult (if not impossible) to determine the pathologic basis of disease. Moreover, our diagnoses would have to be based solely on gross and microscopic appearance of the tissues, without access to clinical histories of the cadaveric donors, including age, past medical history, and proposed cause of death.

Methods

Anatomy instruction at Sidney Kimmel Medical College of Thomas Jefferson University is based on overview lectures and cadaver dissection [6]. Cadavers were obtained from the Humanity Gifts Registry, embalmed using “Maryland State Anatomical Solution” (Hydrol Chemical Company), and maintained at 10°C. During dissection, students documented anatomic variations and pathologic findings. Organs with evidence of gross pathology were removed at the end of the course and kept moist with water containing 10% (v/v) propylene glycol. A total of 6 cases were selected for this Pathology Honors project: ovary (n=1), kidney (n=1), liver (n=1), and lung (n=3). Paraffin embedded tissues were sectioned at 6 microns and stained with Hematoxylin and Eosin (H&E). Slides were examined using a Nikon light microscope at 2x, 10x, and 20x magnification, and photographed using a digital camera.

Results

Case 1: Lung with multiple, white pleural plaques

Gross examination of the hypoplastic, right lung from a cadaver with widespread abdominal metastases reveals multiple, white, palpable plaques on the visceral pleura (Figure 1a). Biopsy and microscopic examination of one pleural plaque demonstrates wellcircumscribed pleural nodules surrounded by normal pulmonary tissue (Figure 1b). On average, the tumor nodules measured 0.5 cm. The presence of detailed alveolar histology in this cadaveric specimen (Figure 1b, inset) indicates that the embalming process was sufficient to preserve tissues with morphology suitable for histopathologic analysis. At higher magnification, the tumor nodules show welldifferentiated glands (Figure 1c) and extensive interstitial fibrosis. These findings suggest a “low-grade carcinoma with desmoplasia”. Some of the glandular lumens contain characteristic necrotic debris, referred to as “dirty necrosis”. Together, these gross and microscopic findings are consistent with a diagnosis of metastatic adenocarcinoma from the colon. Although immunohistochemical assays were not performed as part of this study, CK20 is an intracellular tumor marker that could be used to distinguish primary from secondary (metastatic) adenocarcinoma [7].