Gary L. Bratthauer

Epithelioid variant of malignant peripheral nerve sheath tumor (malignant epithelioid schwannoma).

Twenty-six cases of malignant peripheral nerve sheath tumor with a predominant epithelioid pattern were studied to determine the range of its histologic patterns, immunophenotype, and biologic behavior. The tumor presented as an asymptomatic mass either in superficial (16 cases) or in deep soft tissue (10 cases) of the extremity. Characteristically, those in deep soft tissue were composed of vague nodules of varying cellularity made up of cords or strands of rounded epithelioid cells with prominent nucleoli. Those in superficial soft tissue were uninodular masses composed of tight clusters of cells showing cell-to-cell molding but possessing the same prominence of nuclei and mitotic activity as those in deep soft tissue. Several were associated with a preexisting benign nerve sheath tumor. A number of cases deviated from the above description, including cases that resembled a clear cell carcinoma, a malignant rhabdoid tumor, and a pleomorphic sarcoma. The majority of cases (80%) strongly expressed S-100 protein and neuron-specific enolase, but all lacked a melanoma-associated antigen (as defined by HMB-45) and cytokeratin. Stains for type IV collagen defined linear immunoreactivity around single cells and groups of cells. This pattern did not differ substantially from that of melanomas and therefore did not serve as a reliable discriminant. Follow-up information indicated a more favorable course for those in superficial soft tissue compared with those in deep sites. Two of 16 patients in the former group developed metastatic disease compared with three of 10 in the latter group. Tumors in superficial soft tissue may be eminently treatable and curable, depending on size.

Palisaded myofibroblastoma. A benign mesenchymal tumor of lymph node.

We report 22 examples of an unusual and distinctive benign mesenchymal tumor arising exclusively from lymph nodes of the groin. The tumor, which presents clinically as a swelling, is composed of spindled cells arranged in solid sheets or short, vaguely palisaded fascicles similar to a neurilemoma. The spindled cells blend gradually with large mats of eosinophilic material that appear as thick bands, ellipses, or circular profiles, depending on the plane of section. These eosinophilic structures, which represent a highly characteristic feature of the tumor, contain deeply eosinophilic, collagen-rich cores surrounded by a weakly eosinophilic, actin-rich cuff. The actin within these eosinophilic structures is derived by coalescence of intracellular actin globules extruded from neighboring cells. In all cases, a thin, compressed rim of normal lymph node was identified. Immunohistochemical analysis indicates that the cells express actin but lack S-100 protein, synaptophysin, desmin, keratin, and epithelial membrane antigen. Delicate, linear striations were identified in only two cases by conventional histochemical techniques. The foregoing features suggest that the tumor is related to a myofibroblast or a specialized smooth-muscle cell. These tumors, therefore, probably arise from smooth-muscle-like cells, which are normally present in some lymph node capsules or stroma. Follow-up information on 17 patients indicated that all are alive and well without any evidence of recurrence or metastasis.

Use of monoclonal antibody against human inhibin as a marker for sex cord-stromal tumors of the ovary.

Inhibin is a glycoprotein hormone produced by normal ovarian granulosa cells and testicular sertoli cells. In the ovary, it inhibits the secretion of follicle-stimulating hormone. Patients with granulosa cell tumors (GCT) have elevated serum levels of inhibin and this finding has been used to detect recurrent tumor. This study attempts to determine whether inhibin antibody (IAB) can preferentially mark GCT and Sertoli-cell or Sertoli-Leydig cell tumors (SCT) in paraffin-embedded tissues and facilitate distinction of GCT from small cell carcinoma of hypercalcemic type (SCC), SCT from Sertoliform endometrioid carcinoma (SEC), and primitive gonadal-stromal tumors from a variety of poorly differentiated neoplasms. Applying microwave-enhanced immunohistochemistry, a total of 126 paraffin-embedded and microwave-enhanced archival ovarian tumors and tissues were studied by using monoclonal IAB. The tumors included 32 adult GCT, 7 juvenile GCT, 4 metastatic GCT, 8 SCT, 7 SCC, 6 primitive gonadal stromal tumors (PGST), 5 fibrothecomas, 6 lipid cell tumors (LCT), 5 extrauterine endometrial stromal sarcomas (ESS), 5 hemangiopericytomas (HPC), 1 metastatic malignant melanoma, 1 metastatic malignant lymphoma, and 27 epithelial tumors including 8 SEC, 5 mucinous tumors, and 4 Brenner tumors. Seven pregnancy luteomas (nodular theca lutein hyperplasia of pregnancy), 3 corpora lutea and 2 ovarian follicles were also studied. The intensity of immunostaining was scored from one to three and the percentage of the immunoreactive tumor cells was determined and expressed in 10% increments. Among 32 adult GCT, 31 (97%) tumors reacted positively with IAB. The percent of positive cells ranged from 30% to 100% (average 80%). Similarly, all four metastatic GCT, 7 juvenile GCT and 4 of 5 fibrothecomas were immunoreactive with monoclonal IAB. Seven of 8 (88%) SCT, 5 of 6 (83%) PGST, all 6 LCT, 7 pregnancy luteomas, 3 corpora lutea and the 2 ovarian follicles were also positive with IAB. The most intense positivity was observed in luteinized stromal cells regardless of tumor type. No immunoreactivity was observed in any of the 7 SCC, 5 ESS, 5 HPC, 1 metastatic malignant melanoma, 1 metastatic malignant lymphoma and the epithelial component of all 27 epithelial tumors including 8 SEC. Among the mucinous tumors of the ovary, however, 3 tumors with luteinized stromal cells showed immunoreactivity in these cells, but no positivity was seen in the mucinous epithelium. We conclude that IAB is an excellent marker for sex cord differentiation in ovarian tumors. It can be used effectively in the diagnosis of GCT and its distinction from epithelial neoplasms particularly SCC. The IAB may also be helpful in differentiating LCT from epithelial malignancies. However, it cannot be used to distinguish GCT from SCT.

Lobular intraepithelial neoplasia: previously unexplored aspects assessed in 775 cases and their clinical implications.

Abstract. Lobular intraepithelial neoplasia (LIN) is currently considered a risk factor for the development of invasive breast cancer of varying morphologies (ductal or lobular) and prognoses in either breast. The reason for the high frequency (50%) of subsequent development of invasive ductal cancers remains unclear and the issue unexplored. A total of 775 LIN cases were retrieved from the Armed Forces Institute of Pathology files and separated into three groups using our three-tiered grading system. The presence or absence of simultaneous invasive cancer (ductal or lobular type) and various grades of ductal intraepithelial neoplasia (DIN) were noted for each case and correlated with the grade of LIN. Of the 775 cases, 80% qualified as LIN 2, with the other 20% being relatively evenly split between LIN 1 and LIN 3. Of the 775 cases, 163 cases were pure LIN, while invasive carcinoma was present in 140 cases. The remaining 472 cases were associated with various grades of DIN. The frequency of associated invasive carcinomas (ductal and lobular) increased from 14% in LIN 1 to 23% in LIN 3. Remarkably, while the frequency of invasive lobular carcinoma increased dramatically from 11% in LIN 1 to 86% in LIN 3, the frequency of invasive ductal carcinoma markedly decreased with advancing grade of LIN from 89% in LIN 1 to 14% in LIN 3. Among the cases of LIN unassociated with invasive carcinoma, DIN was present in 75% of LIN 1, 75% of LIN 2, and 66% of LIN 3 cases. The grade of DIN was directly proportional to the grade of LIN. Based on the higher frequency of invasive lobular carcinoma associated with LIN 3, biopsies with LIN 3 should be evaluated diligently for the presence of an associated invasive lobular carcinoma. Furthermore, an excisional biopsy should be performed when LIN 3 is observed in a core biopsy. The high frequency of DIN associated with LIN might suggest that the subsequent invasive ductal carcinomas originate from the associated DIN and that some of this may represent a different phenotype of the same cells that form the LIN lesion. It is also possible that the neoplastic cells may reflect or retain stem cell characteristics with plasticity and the capacity to attain or progress into either a ductal or lobular invasive phenotype.

Cell clusters overlying focally disrupted mammary myoepithelial cell layers and adjacent cells within the same duct display different immunohistochemical and genetic features: implications for tumor progression and invasion

IntroductionOur previous studies detected focal disruptions in myoepithelial cell layers of several ducts with carcinoma in situ. The cell cluster overlying each of the myoepithelial disruptions showed a marked reduction in or a total loss of immunoreactivity for the estrogen receptor (ER). This is in contrast to the adjacent cells within the same duct, which were strongly immunoreactive for the ER. The current study attempts to confirm and expand previous observations on a larger scale.MethodsParaffin sections from 220 patients with ER-positive intraductal breast tumors were double immunostained with the same protocol previously used. Cross-sections of ducts lined by ≥ 40 epithelial cells were examined for myoepithelial cell layer disruptions and for ER expression. In five selected cases, ER-negative cells overlying the disrupted myoepithelial cell layer and adjacent ER-positive cells within the same duct were separately microdissected and assessed for loss of heterozygosity and microsatellite instability.ResultsOf the 220 cases with 5698 duct cross-sections examined, 94 showed disrupted myoepithelial cell layers with 405 focal disruptions. Of the 94 cases, 79 (84%) contained only ER-negative cell clusters, nine (9.6%) contained both ER-negative and ER-positive cell clusters, and six (6.4%) contained only ER-positive cell clusters overlying disrupted myoepithelial cell layers. Of the 405 disruptions, 350 (86.4%) were overlain by ER-negative cell clusters and 55 (13.6%) were overlain by ER-positive cell clusters (P < 0.01). Microdissected ER-negative and ER-positive cells within the same duct from all five selected cases displayed a different frequency or pattern of loss of heterozygosity and/or microsatellite instability at 10 of the 15 DNA markers.ConclusionsCells overlying focally disrupted myoepithelial layers and their adjacent counterparts within the same duct displayed different immunohistochemical and molecular features. These features potentially represent an early sign of the formation of a biologically more aggressive cell clone and the myoepithelial cell layer breakdown possibly associated with tumor progression or invasion.

Expression of LINE-1 retrotransposons in human breast cancer

Background. Several diseases have been linked to the insertion of human LINE‐1 retrotransposons (L1Hs) into structural genes. Recently, the element has been shown to be expressed in a variety of adult and pediatric germ cell cancers, leading to speculation that L1Hs‐induced insertion mutations may play a role in the etiology of some neoplasias.

Postirradiation malignant fibrous histiocytoma expressing cytokeratin: implications for the immunodiagnosis of sarcomas

A malignant fibrous histiocytoma of the sacrum complicating the course of radiation therapy for endometrial carcinoma is presented. Although the tumor fulfilled the clinical, radiologic, and histologic criteria for a postirradiation malignant fibrous histiocytoma of bone, it also expressed cytokeratin. That this immunoreactivity reflected keratin synthesis by the tumor and not an unusual pattern of cross-reactivity with another intermediate filament such as vimentin is strongly suggested by the reproducibility of the immunoreactivity utilizing both polyclonal and monoclonal antibodies and extinction of the immunoreactivity following absorption of the primary antiserum with keratin proteins. This is the first reported instance of keratin expression by a malignant fibrous histiocytoma; it indicates that sarcomas apart from synovial sarcoma and epithelioid sarcoma may sometimes express this protein.

Osteocalcin and osteonectin immunoreactivity in extraskeletal osteosarcoma: A study of 28 cases

Extraskeletal osteosarcoma (EOSA), a rare malignant soft tissue tumor, is by definition unattached to the skeleton and composed of malignant cells of osteoblastic phenotype which produce osseous matrix (ie, neoplastic bone). Because of its location, it can mimic other soft tissue tumors, and its matrix can be mistaken for hyalinized collagen. Antiosteocalcin (OC) and antiosteonectin (ON), antibodies against two abundant human bone proteins, are explored in the diagnosis of EOSA. Twenty-eight cases coded as EOSA (n=24) or probable EOSA (n = 4) were identified from the Soft Tissue Registry of the Armed Forces Institute of Pathology (Washington DC). All cases had paraffin blocks available for immunohistochemistry. OC and ON (Biodesign International, Kennebunk, ME, clones OC1 and OST1) immunostaining for tumor cells and matrix was graded on a four-tiered grading system: 1 = focal (< 50%) weak staining; 2 = focal strong staining; 3 = diffuse (> or = 50%) weak staining; and 4 = diffuse strong staining. Patient ages ranged from 9 to 80 years, with a mean age of 57 years. There were 9 female patients and 19 male patients. The tumor sizes ranged from 1.5 to 15 centimeters, with a mean size of 5.8 centimeters. Locations included the lower extremity (n=14), trunk (n=9), upper extremity (n=4), and head and neck (n=1). Subtypes included 12 osteoblastic, 4 fibroblastic, 2 chondroblastic, 2 well differentiated, 1 telangiectatic, 1 small cell, and 6 giant cell rich EOSAs; the latter resembled giant cell rich malignant fibrous histiocytomas with neoplastic bone formation. All tumors had both neoplastic cells and bony tumor matrix to evaluate. OC was 82% sensitive for EOSA neoplastic cells (1 to 4+), with immunostaining of neoplastic cells away from bone in 91% of cases, and 75% for bony tumor matrix (2 to 4+). ON was 93% sensitive for EOSA neoplastic cells (2 to 4+), yet only 39% for bony tumor matrix (1 to 4+). In 100% giant cell rich EOSA, neoplastic cells were positive for OC and ON (2 to 4+). OC showed 100% specificity for osteoblasts as it was nonreactive in all nonbone cells. ON was not specific for osteoblasts but consistently immunostained other cell types in our EOSA tumors: fibroblasts (100%), pericytes (96%), endothelial cells (92%), chondrocytes (5/5), basal layer of skin epithelium (1/4), nerves (2/2), and osteoclastic giant cells (64%). ON also stained several other cell types in normal and neoplastic tissues in our battery of preliminary stainings; OC was negative in all nonosteoblastic tissues and tumors. Both OC and ON were specific for osteoid matrix as they were nonreactive in both collagen and cartilage matrix. OC is a sensitive and specific marker for bone cells and would be helpful in identifying EOSA, even in the absence of neoplastic bone on small biopsies. ON and OC (more sensitive) will both distinguish malignant bone from collagen and cartilage matrix, essential to the diagnosis of EOSA.

ETIOLOGY OF BREAST CARCINOMA : NO APPARENT ROLE FOR PAPILLOMAVIRUS TYPES 6/11/16/18

A recent study has shown that human papillomavirus (HPV) types 16 and 18 can immortalize normal breast epithelium, and raised the possibility that HPV may be etiologically related to some cases of breast cancer. In order to investigate this possibility, we performed polymerase chain reaction (PCR) assays for HPV types 6, 11, 16 and 18 in 15 papillomas, 15 papillary carcinomas, and 13 infiltrating ductal carcinomas of the breast. No HPV-related DNA sequences were identified by Southern blotting of the PCR products. It therefore seems unlikely that a significant percentage of human breast carcinomas is etiologically related to infection with one of these HPV types.

Carcinoma Arising in Microglandular Adenosis: An Immunohistochemical Analysis of 20 Intraepithelial and Invasive Neoplasms.

Microglandular adenosis (MGA) of the breast is an uncommon, benign lesion that may mimic invasive carcinoma and has recently been recognized as having significant premalignant potential. When carcinomas arise in MGA, there is often a transition from ordinary MGA to atypical MGA (AMGA) to carcinoma. Nineteen cases of carcinoma arising in MGA are reported: 7 invasive carcinomas, 7 intraductal carcinomas (DCIS), and 5 with both invasive and intraductal carcinoma. A single case of AMGA without carcinoma is also reported. The 20 patients ranged in age from 36 to 81 years (mean 52). The most common clinical presentation was either a palpable mass (13 patients) or a mammographic abnormality (4 patients). All 20 cases contained AMGA, and in some cases AMGA was the predominant lesion. In 18 of the 19 cases with carcinoma, there was a clear transition from AMGA to the carcinoma. TWelve cases contained ordinary MGA, but in only 2 cases was MGA a prominent component of the lesion. In contrast to ordinary MGA, the glands of AMGA were more irregularly shaped, closely packed, and cytologically atypical and tended to lack secretions. A solid, occlusive proliferation of cells in the tubules was seen in 10 cases. All 12 examples of in situ carcinoma were either grade 2 or 3 and typically showed a solid proliferation of severely atypical cells within the glands; a cribrifrom pattern was also present in 1 case. The invasive carcinomas were morphologically diverse and included 2 with a basaloid morphology and 2 metaplastic carcinomas. Various immunostains were performed, and each lesion (AMGA, in situ, and invasive carcinoma) was separately assessed for immunoreactivity. As expected, S-100 was positive in the vast majority of AMGA and in situ carcinomas and in all 12 invasive carcinomas. S-i 00 was also positive in the majority of cases although the staining was weaker. Laminin and type IV collagen highlighted the basement membrane around the AMGA and in situ carcinoma and are useful stains in difficult cases. Except for a single case, ER and PR were negative in all lesions. Cytokeratin 7 (CK 7) was positive, while cytokeratin 20 (CK 20) was negative in all cases. Immunostains for CK903 showed no reactivity in any of the invasive carcinomas, in situ carcinomas, or atypical MGA but was focally present in the associated MGA in 2 of the 8 cases studied. Immunostains for MIB-1 and p53 were semiquantitatively assessed and both were positive in AMGA but tended to show a more intense staining in the carcinomas. Five cases were also studied for immunoexpression of alpha-I antitrypsin (AAT), alpha-I antichymotrypsin (ACTP), lysozyme, and salivary gland amylase. All 5 invasive carcinomas were positive for ACTP, though the staining was very focal in about 10% of the cells in a basaloid carcinoma. The in situ carcinoma were as well as the AMGA in 4 of the 5 in cases were positive for ACTP. Three of the 5 invasive carcinomas were positive for AAT in 10% to 40% of the cells. The most intense positivity for AAT and ACTP was in cells with coarsely granular apocrine apspearance evident in 2 of the 5 cases. Four of the 5 invasive carcinomas were positive for lysozyme in 10% to 50% of the cancer cells; the in situ carcinoma and the associated AMGA showed similar immunoreaction in each case. None of the 5 cases showed convincing positivity for salivary gland amylase. The MGA in all 5 cases was negative for AAT and ACTP; the MGA in 1 of the 5 cases was positive for lysozyme. This study confirms the potential of MGA to develop into an invasive carcinoma, more clearly defines the features of AMGA, highlights the importance of AMGA in the evolution of carcinoma from MGA, and expands our knowledge of the immunophenotype of AMGA and the carcinomas arising from it. The diagnostic criteria briefly noted previously for diagnosis of AMGA and carcinoma arising in MGA are expanded and formally proposed.