Jan A. M. Van Unnik

The relevance of the DNA index and proliferation rate in the grading of benign and malignant soft tissue tumors

The relevance of the DNA index (DI) to malignancy grading and the relationships between mitotic score, Ki‐67 score, and the proportion of cells in the G1‐phase (G1PF) of the cell cycle, as proliferative indicators, were investigated in benign (n = 8) and malignant (n = 46) soft tissue sarcomas. Although DI was not found to be related to the histology of the sarcomas, it was associated with malignancy grade, i.e., 14%, 25%, 42%, and 86% of benign, Grade 1, Grade 2, and Grade 3, respectively had a DI>1. The relevance of aneuploidy in benign tumors is discussed and the literature reviewed. A subgroup of the malignant tumors (n = 13) had both a low mitotic score and a low Ki‐67 value. However, a distinct correlation between Ki‐67 and the mitotic score could not be shown. For malignant tumours G1PF was related to DI, i.e., low G1PF occurred in tumors with diploid DNA content. Low Ki‐67 scores were observed in 59% of diploid tumors and in 20% of aneuploid tumors. However, it appeared that G1PF and Ki‐67 were not correlated. In conclusion, (1) benign and Grade 1 tumors were predominantly diploid with high G1PF and low Ki‐67 values, (2) most of Grade 3 tumors were aneuploid (86%) with low G1PF and high Ki‐67 values, and (3) the group of Grade 2 tumors could be divided into two subgroups either with the characteristics displayed by benign and Grade 1 tumors (DI = 1, low Ki‐67 scores, and high G1PF) or with the characteristics exhibited by Grade 3 tumors (DI>1, high Ki‐67 scores, and low G1PF). Hence, supplementary to the grading of soft tissue tumors, DI, G1PF, and Ki‐67 score could be useful as prognostic parameters in soft tissue tumors.

Extranodal non-Hodgkin's lymphoma of the oral tissues an analysis of 20 cases

A series of 20 patients with extra-nodal non-Hodgkins lymphoma (ENHL) of the oral cavity was analysed with the emphasis on histopathological variability and prognostic factors. The current diagnostic schemes as devised for nodal NHL proved also to be useful in diagnosing ENHL in the oral cavity. With respect to histopathology, intra-oral ENHL differs from nodal NHL in a lower incidence of nodular growth pattern and a relative predominance of the lymphoma sub-type with large vesicular indented nuclei. These are features, however, that are shared with ENHL in other body sites and thus are not unique to the oral location. Another salient histological feature was the presence of proliferating bizarre spindle cells with formation of whorling bundles of reticulin, thus creating a pseudosarcomatous growth pattern in some cases. The clinical stage proved to be the main discriminating factor between those who survived and those who died of their lymphoma. Of the patients who were in stage IE on admission, 70% survived as opposed to only 20% of those who were in stage II or IV. A better prognosis for cases with soft tissue involvement as opposed to intraosseous lymphoma is probably due to a consistently lower clinical stage in the former group. The prognostic value of the clinical stage emphasizes the importance of adequate clinical staging procedures.

Primary B‐cell malignant lymphoma of the maxilla with a sarcomatous pattern and multilobated nuclei

Three cases of primary malignant lymphoma of the maxilla are reported. The primary intraosseous origin of these tumors was demonstrated by x‐ray examination and surgical exploration. The initial interpretation as odontogenic infection led to a delay in starting therapy of 9 months in one case. Biopsies of two cases were initially interpreted as sarcoma because of a dense reactive fibrosis between the tumor cells. Subsequently, hemimaxillectomy was performed in one case. Histologically and ultrastructurally the tumor cells showed marked nuclear abnormalities with cleavage, folding, and lobulation. Immune histochemical studies of two cases showed a monoclonal immunoglobulin expression, IgG‐K; T‐lymphocyte‐associated antigens were not detected on the tumor cells. The findings indicate the existence of a primary B‐cell malignant lymphoma of bone with multilobated nuclei. The lymphoid nature may be masked by a dense proliferation of connective tissue. The relation of these tumors to the classifications for malignant lymphoma of lymph node is discussed.

Distribution of actin isoforms in sarcomas: An immunohistochemical study

The actin immunophenotype of eight benign mesenchymal tumors, 14 nonsarcomatoid tumors, and 46 sarcomatoid tumors was studied, using monoclonal antibodies (MoAb) specific for alpha-smooth muscle actin (clone 1A4), alpha- and gamma-smooth muscle actin (designated CGA7), and muscle actin (designated HHF35) on frozen sections. Tumor cells of nonsarcomatoid tissues were not reactive, but all leiomyomas and five of the seven leiomyosarcomas reacted with the three MoAbs. One leiomyosarcoma was immunoreactive for the MoAb 1A4 only. One of the six malignant schwannomas showed staining for muscle actin (HHF35). The 22 malignant fibrous histocytomas (MFH) expressed these actin isoforms in various degrees. One case immunoreacted with all three MoAbs, three reacted with 1A4 only, seven reacted with CGA7 and HHF35, and two reacted with HHF35 only. Nine MFHs were not immunoreactive for any of the MoAbs specific for (smooth) muscle and actin. In addition, the expression of desmin and collagen type IV was investigated for the group of leiomyosarcomas and MFHs. Desmin was found in five leiomyosarcomas and in two MFHs. Collagen type IV was seen in all leiomyosarcomas, and was seen weakly in a few small areas in four MFHs. When we take into account the expression of all markers tested [( smooth] muscle actin, desmin, and collagen type IV), then six of the 22 MFHs were unreactive for all these markers. Five of these six tumors were located intramuscularly, whereas only half of the total number of MFH cases had an intramuscular location. The fact that 15 of 22 MFHs displayed one or more markers linked with (smooth) muscle differentiation suggests that some of the MFHs may be classified as poorly differentiated leiomyosarcomas, and that MFH is not a unique entity.

Expression of insulin-like growth factor 1 in sarcomas

The expression of insulin‐like growth factor‐1 (IGF‐1) was studied in normal tissues, in eight benign lesions and in 50 sarcomas. In palmar fibromatosis the spindle cells in cell‐dense areas exhibited a strong immunoreactivity. IGF‐1 was variably found in leiomyosarcomas (7/8), malignant schwannomas (7/9), synovial sarcomas (2/3), liposarcomas (3/6), fibrosarcomas (1/3), malignant fibrous histiocytomas (10/18) and in one angiosarcoma. Two rhabdomyosarcomas failed to express IGF‐1 and only the spindle cell component of synovial sarcomas was positive. Immunoreactivity for IGF‐1 in 10 malignant filrous histiocytomas (MFH) appeared to be related to co‐expression of smooth muscle actin. These findings imply that MFHs can be subdivided into a group of tumours which are devoid of morphological and immunophenotypic evidence of differentiation and a group which manifest immunophenotypic differentiation.

Determination and characterization of hexokinase in thyroid cancer and benign neoplasms.

Hexokinase (ADP: D‐hexose‐6‐phosphotransferase, EC 2.7.1.1) was studied in human thyroid carcinomas (n = 11), follicular adenomas (n = 32), and normal thyroid tissue (n = 21). The specific activity was significantly increased in carcinoma (0.163 ± 0.083 U/mg protein) compared with normal tissue (0.030 ± 0.010 U/mg protein) (P < 0.001). Specific activities of follicular adenomas are rather heterogeneous, but when subdivided into three groups according to histopathologic criteria, a significant difference was found between follicular adenomas group I and II and follicular adenomas group III. A lesser cellular differentiation of adenomas is indicated by the lower degree or even absence of colloid production and follicle formation. A higher proliferation rate may be assumed on the grounds of the irregularities in outline, the often defective pseudocapsule, and signs of compression of the surrounding tissue. The highest specific activity in adenomas was found in the group with the highest proliferative activity, i.e., group III, whereas the lowest specific activities were found in adenomas with the lowest grade of proliferation, i.e., group I; the former was comparable with values found in carcinomas and the latter was comparable with values found in normal thyroid tissue. An interesting difference was found when the compartmentation of hexokinase was compared in carcinomas of different degree of differentiation. In papillary carcinomas a significantly lower proportion of hexokinase (HK) is present in the cytosol in comparison to follicular and undifferentiated carcinomas. In carcinomas more HK II and less HK I was found in comparison with normal thyroid tissue. In contrast hexokinase isozyme composition and compartmentation in adenomas were not different from normal thyroid tissue.

Multilobated non-Hodgkin's lymphoma. A clinicopathologic entity.

Multilobated non‐Hodgkins lymphomas (NHL) have recently been recognized as an NHL variant. During a period of 10 years we observed 30 individuals with NHL in which more than 30% of the malignant cells had a characteristic multilobation. The immunologic phenotype was determined in 14 of these cases. One was of T‐cell lineage, and the others exhibited B‐lymphoid markers. Sixty‐eight percent of the patients presented with extranodal localizations. In the clinical follow‐up a complete remission was observed in 78% of patients with a mean duration of 37 months (range, 5 to 120 months). The actuarial survival after 5 years was 45%. From these data we conclude that multilobated NHL are comparable to diffuse, large cleaved‐cell NHL of an intermediate grade malignancy according to the Working Formulation or are comparable to the diffuse centrocytic‐centroblastic NHL according to the Kiel classification. The neoplastic cells are to be considered as variants of follicle center cells, but the clinicopathologic correlation indicates that multilobated NHL represent a distinct nosologic entity.

Pyruvate kinase in normal human thyroid tissue and thyroid neoplasms.

Pyruvate kinase (ATP: pyruvate‐2‐O‐phosphotransferase, EC 2.7.1.40) was studied in human thyroid carcinomas (n = 9), follicular adenomas (n = 32), and normal thyroid tissue (n = 12). The specific activity in carcinomas (mean 0.94 ± 0.44) is significantly increased (P < 0.0001) in comparison with pyruvate kinase in normal tissue (mean, 0.14 ± 0.05). Specific activities of follicular adenomas are rather heterogeneous. When these tumors were divided into three groups of increasing proliferative activity as judged by histopathologic criteria, highest specific activities of pyruvate kinase were found in the group with the highest proliferative activity. On the other hand, specific enzyme activities of the least active tissues (colloid‐containing follicular adenomas) were comparable to normal. The isoenzyme composition of normal thyroid tissue is characterized by the presence of K4, K3M, and K2M2 types of pyruvate kinase. In carcinomas, mainly K4, and K3M are found. Undifferentiated tumors express more K4 type compared with follicular and papillary carcinomas. Follicular adenomas with high specific activity show the same electrophoretic pattern as found in follicular carcinomas. Pyruvate kinase from malignant tumors is more inhibited by the amino acid L‐alanine than the enzyme from normal thyroid tissue as a consequence of the presence of more K subunits in the malignant tissues. The K4 type from normal thyroid tissue is not kinetically different from the K4 type of carcinomas.

Non‐Hodgkin's lymphoma of Waldeyer's ring

The authors retrospectively analyzed 103 patients to investigate the value of examination of Waldeyers ring with biopsies as a staging procedure in patients with non‐Hodgkins lymphoma. Twenty‐three patients had clinical involvement of Waldeyers ring. In 55 of 80 remaining patients, this staging procedure was performed but positive biopsy specimens were found only in patients with advanced disease. No correlation was found between positive biopsy specimens and the histologic subtype. No positive biopsy specimens of Waldeyers ring were obtained in patients with cervical lymphadenopathy without clinical involvement of the nasopharynx and in patients with localized lymphoma of the gastrointestinal tract. Blind biopsies of Waldeyers ring as a staging procedure proved to be of no value in the patients. The results of therapy in 23 patients with involvement of Waldeyers ring were good. Unfavorable histologic subtypes (intermediate or high‐grade malignancy) were predominant (91%). Eighteen of 22 patients (82%) achieved complete remission, with a relapse‐free survival rate at 60 months of 95%. For the whole group of patients, the actuarial survival rate at 72 months was 71%.

Enzyme Histochemistry of Soft Tissue Tumors: A Study of 68 Cases

The pathologic analysis of soft tissue tumors (STT) has been neglected for a long time, but the past decade has witnessed advances in both the diagnosis and treatment of these tumors. Consequently, the number of related medical publications has risen dramatically. In attempting to classify STT, all conceivable diagnostic modalities must be considered. The introduction and application of additional techniques provide new insights into the histogenesis of many STT and improve the present classification and diagnosis of these tumors.