Pseudolymphoma of the stomach

In certain sites, including the stomach, primary extranodal malignantlymphoma has a good prognosis. Some of these cases may be examples of pseudolymphoma, and though there have been numerous large series of primary malignant lymphomas of the stomach recorded, little reference to gastric pseudolymphoma has been made and few cases described. This paper is a review of current knowledge of this lesion and includes five cases studied personally in which the distinction from lymphoma is at issue.     

Pseudolymphoma of the stomach. Nodular type

A case of nodular type of pseudolymphoma of the stomach was reported. The tumor measured 3.2 by 2.0 by 0.7 cm and was located astride the greater curvature of the muscularis propria. It was composed of many germinal centers surrounded by mature lymphocytes. There was no evidence of a previous peptic ulcer. The patient is now alive without any symptoms 8 years after the operation.     

Pseudolymphoma (inflammatory pseudotumor) of the liver

Two small pseudolymphomas of the right liver lobe were incidentally detected at autopsy in a 85 year old female patient with a large ulcerating carcinoma of the stomach. Most of the lymphocytes and plasma cells produced IgA and lambda light chains, a few also kappa light chains. These tumors may also be classified as inflammatory pseudotumors of the liver.     

Histiocytosis X of the thyroid masquerading as thyroid carcinoma

The case of a 28-year-old woman with histiocytosis X confined to the thyroid is described. A partial thyroidectomy specimen from this patient was at first interpreted as showing poorly differentiated thyroid carcinoma. Subsequent investigations, including electron microscopy, revealed the true nature of the lesion. Even on retrospective examination, the two conditions can simulate each other very closely and may be easily confused.     

Plasmacytoma of the thyroid

Three cases of plasmacytoma of the thyroid are described and their clinical and histological features recorded. Two were considered to be true extramedullary plasmacytomas, the third the initial manifestation of a disseminated myelomatous process. Plasmacytomas of the thyroid are shown to have many features in common with malignant lymphomas in this site, including an association with Hashimoto thyroiditis in more than half the reported cases. No certain method of assessing the prognosis in any individual case has yet been described.     

Microcarcinoma of the thyroid

Thyroid microcarcinoma, defined as a thyroid tumor measuring 1 cm or less, is an extremely indolent tumor. Papillary microcarcinoma, the most common subtype, is often identified incidentally in a thyroid removed for benign clinical nodules or diffuse processes (eg, thyroiditis). In this clinical situation, over 99% are cured by simple lobectomy. In the less common scenario, the microcarcinoma is the primary lesion to a lymph node metastasis presenting clinically as a neck mass; in this situation, the tumor should be treated as a clinical cancer. Other rare microcarcinomas can occur and, of these, the most recently described is micromedullary carcinoma. In the familial setting, these lesions are identified in prophylactic thyroidectomies and are not unexpected findings. However, when found as sporadic tumors, their implications are still unknown. The histologic features, pathologic mimics, and molecular facets of these microscopic neoplasms are discussed in this review.     

Histoplasmosis of the thyroid

Fungal infection of the thyroid is rare. Most reported cases have involved Aspergillus, Coccidioides, and Candida species in the setting of disseminated disease. Infection of the thyroid with Histoplasma capsulatum is rarely reported as part of disseminated disease, even in geographic areas where histoplasmosis is endemic. We report a 52-year-old woman with a previous Hashimoto's disease and non-Hodgkin's lymphoma in which a diffuse enlarged thyroid gland with a large nodule was the only apparent locus of histoplasmosis. Fine-needle aspiration of the thyroid was an important diagnostic tool in establishing the diagnosis of histoplasmosis of the thyroid. The patient was initially treated with itraconazole (400 mg/day) for the fungal infection and six cycles of chemotherapy for the lymphoma. At a 6-month follow-up examination, the patient was doing well on suppressive therapy of itraconazole (200 mg/day), with no symptoms and with regression of the thyroid nodule and cervical adenopathy.     

Solid cell nests of the thyroid in medullary thyroid carcinoma

Solid cell nests of the thyroid gland were studied in 44 patients with medullary thyroid carcinoma. In 10 (22.7%) patients, solid cell nests were revealed in the vicinity of tumour foci (five cases) or in the contralateral thyroid lobe and isthmus (four cases); in one case the location was indeterminate. In all seven cases in which immunohistochemical studies were carried out, solid cell nests showed negative staining for thyroglobulin, calcitonin and chromogranin A, findings which were distinct from those in medullary thyroid carcinoma. It is therefore suggested that solid cell nests of the thyroid are not precursors of this tumour.     

Physiological relevance of thyroid stimulating hormone and thyroid stimulating hormone receptor in tissues other than the thyroid

Decades of research have provided strong evidence for a reciprocal relationship between the immune system and hormones of the hypothalamus-pituitary-thyroid (HPT) axis. Thyroid stimulating hormone (TSH), in particular, has been shown to have a variety of immune-regulating cytokine-like activities that can influence the outcome of T cell development in the thymus and intestine, and can affect the magnitude of antibody and cell-mediated responses of peripheral lymphocytes. Production of TSH and the expression of the TSH receptor are widely but selectively distributed across many different types of hematopoietic cells in the bone marrow, as well as among subsets of dendritic cells, monocytes and lymphocytes in the spleen and lymph nodes. In addition to their role in immunity, the involvement of TSH-producing hematopoietic cells in the microregulation of thyroid hormone activity represents a novel and potentially important aspect of the TSH-mediated immune-endocrine circuit.     

Non-diagnostic cytological outcome of thyroid biopsy and the risk of thyroid malignancy

This study assessed the incidence of neoplasms, including malignant tumors, in lesions within the thyroid gland from which non-diagnostic biopsy aspirates were obtained. An auxiliary goal of the study was an evaluation of the diagnostic efficacy of repeated biopsy in cases when the first biopsy was non-diagnostic. Thus, results of 4603 fine-needle aspiration biopsies (FNABs) were submitted to histopathological verification. The verification revealed the rate of malignancy at 7.1% for non-diagnostic biopsies, i.e., significantly higher (p<0.001) than that in cases FNAB-diagnosed as benign lesions (2.1%). Repeated biopsy, performed when inadequate material has been collected, seems to be less effective than the first biopsy (non-diagnostic specimens; 14.4% vs 8.9%; p<0.01). The occurrence of neoplasms in the goiter was significantly higher (p < 0.0001) in patients with non-diagnostic first FNAB than in those with diagnostic one (50.7% vs 33.5%, p<0.001). And again, in patients with two non-diagnostic FNABs, the occurrence of neoplasms was higher than that in patients with the second diagnostic cytology (63% vs 41.2%, p<0.05). According to our data, patients with non-diagnostic FNAB results should be very carefully monitored, especially when the repeated biopsy is either non-diagnostic again or not performed at all.     

Regeneration of the thyroid gland

Summary The right lobe and the posterior portion of the left lobe of the thyroid gland were excised in male albino rats weighing 220 mg. Postoperative observations periods were 4, 8, 16, 31, and 93 days. At the end of the experiment the weight of the regenerated gland was 93.2% of that in control animals. During the regeneration process mitosis of the follicular epithelium and formation of new follicules were observed in the thyroid remnant. The percentage ratio of the epithelium and the colloid, determined by Tal's method, at first showed a marked rise at the expense of the epithelium, later approaching the indices, characteristics of control animals. The percentage of microfollicules also showed a considerable increase (their percentage in 31 days reached 40). Later it dropped to normal values. Glandular regeneration took place not by growing from the wound surface, but by regenerative hypertrophy.(Presented by Active Member AMN SSSR N. N. Zhukov-Verezhnikov) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 54, No. 8, pp. 87–92, August, 1962     

Epithelioid angiosarcoma of the thyroid

Epithelioid angiosarcomas of the thyroid usually develop in people living in Alpine regions, and only rare cases arising in subjects living in nonmountainous areas have been reported. We describe the clinicopathological features of a series of seven cases collected from non-Alpine areas. All patients were adults. The tumours appeared as haemorrhagic, unencapsulated, sometimes cystic nodules. In two cases multinodularity was present. They were composed of large, epithelioid cells, which lined vascular-like spaces or were arranged in solid sheets. Intracytoplasmic lumina containing red blood cells were identified. Neoplastic cells were diffusely positive for factor VIII-related antigen, Ulex europaeus agglutinin, CD31 and keratin peptides. Ultrastructural studies were performed in four cases and showed features of endothelial differentiation. An average follow-up of 3.8 years disclosed that four patients died of disease after a median survival time of 5 months, whereas 3 patients are still alive with no evidence or residual disease 27, 32 and 66 months after thyroidectomy. The good prognosis in these patients appears to be related mainly to the absence of extraglandular tumour spread at the time of surgery.     

The hemangioendothelioma of the thyroid

Summary 65 cases of hemangioendothelioma (HE) of the thyroid were accepted as such after control of slides of surgical or autopsy specimen or both. In a few of the more recent cases material could be examined by electron microscope and in some the search for factor VIII-related antigen (FVIIIRAG) was carried out.The demonstration of Weibel-Palade bodies in tumour cells in two cases and the evidence of FVIIIRAG in tumour cells of at least two cases, including primary tumour and distant metastasis, finally show, that the hemangioendothelioma of the thyroid is not simply an anaplastic carcinoma with some peculiar features; at least some of these tumours are true endotheliomas.The proposal that the term hemangioendothelioma be eliminated from the classification of thyroid tumours is therefore unfounded.