180 Cytology of Organ Biopsies and Exudates

Sarcoidosis and Tuberculosis

The material of cell biopsies taken from indolent, nonirritated enlarged lymph nodes in the neck or axilla that have developed with little in the way of clinical symptoms, or from subcutaneous infiltration in various regions, can be quite homogeneous. With their thin, very long, ovoid nucleus (four to five times the size of lymphocytes), delicate reticular chromatin structure, and extensive layer of cytoplasm that may occasionally appear confluent with that of other cells, they are reminiscent of the epithelial cells that line the body’s internal cavities and are therefore called epithelioid cells. They are known to be the tissue form of transformed monocytes, and are found in increased numbers in all chronic inflammatory processes—especially toxoplasmosis, autoimmune diseases, and foreign-body reactions—and also in the neighborhood and drainage areas of tumors. They exclusively dominate the cytological picture in a particular form of chronic “inflammation,” sarcoidosis (Boeck disease). A typical finding almost always encountered at the pulmonary hilus combined with a negative tuberculin test will all but confirm this diagnosis. The appearance of a few multinuclear cells (Langhans giant cells) may allow confusion with tuberculosis, but clinical findings and a tuberculin skin test will usually make the diagnosis clear.

Rapidly developing, usually hard, pressure-sensitive neck lymph nodes, seemingly connected with each other with some fluctuant zones and external inflammatory redness, suggest the now rare scrofulous form of tuberculosis. A highly positive tuberculin skin test also suggests this diagnosis. If any remaining doubts cannot be dispelled clinically, a very-fine- needle lymph node biopsy may be performed, but only if the skin shows noninflammatory, pale discoloration.

The harvested material can show the potency of the tissue-bound forms of cells in the monocyte/macrophage series. In addition to mononuclear epithelioid cells, there are giant cell conglomerates made up of polynuclear epithelioid cells in enormous syncytia with 10, 20, or more nuclei. These are called Langhans giant cells. In scrofuloderma (tuberculosis colliquativa), there are also lymphocytic and granulocytic cells in the process of degradation, which are absent in purely productive tuberculous lymphadenitis.

Epithelioid cells dominate the lymph node biopsy: Boeck disease or tuberculosis

a

b

Fig. 64 Boeck disease and tuberculosis. a Lymph node cytology in Boeck disease: a special form of reactive cell pattern with (often predominating) islands and trains of epithelioid cells (arrow), which have ovoid nuclei with delicate chromatin structure and a wide, smoke-gray layer of cytoplasm. b Lymph node cytology in tuberculous lymphadenitis: in addition to lymphocytes and a few epithelial cells (1), enormous syncytes of epithelioid cell nuclei within one cytoplasm (arrow) may be encountered: the Langhans giant cell.

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182 Cytology of Organ Biopsies and Exudates

Non-Hodgkin Lymphoma

Since the CBC is the first step in any lymph node diagnosis, lymph node biopsy is unnecessary in many cases of non-Hodgkin lymphoma (p. 70), because the most common form of this group of diseases, chronic lymphadenosis, can always be diagnosed on the basis of the leukemic findings of the CBC.

However, when enlarged lymph nodes are found in one or more regions without symptoms of reactive disease, and the blood analysis fails to show signs of leukemia, lymph node biopsy is indicated.

The relatively monotonous lymph node cytology in non-Hodgkin lymphomas and tumor metastases mean that histological differentiation is required.

In contrast to Hodgkin disease, with its conspicuous giant cell forms (p. 177), non-Hodgkin lymphomas display a monotonous picture without any signs of a reactive process (p. 70). Clinically, it is enough to distinguish between small cell forms (which have a relatively good prognosis) and large cell forms (which have a poorer prognosis) to begin with. For a more detailed classification, see page 70f.

Histological analysis may be omitted only when its final results would not be expected to add to the intermediate cytological findings in terms of consequences for treatment.

Metastases of Solid Tumors in Lymph Nodes or Subcutaneous Tissue

When hard nodules are found that are circumscribed in location, biopsy shows aggregates of polymorphous cells with mostly undifferentiated nuclei and a coarse reticular structure of the chromatin (perhaps with welldefined nucleoli or nuclear vacuoles), and the lymphatic cells cannot be classified, there is urgent suspicion of metastasis from a malignant solid tumor, i.e. from a carcinoma in a variety of possible locations or a soft tissue sarcoma.

As a rule, the next step is the search for a possible primary tumor. If this is found, lymph node resection becomes unnecessary.

If no primary tumor is found, lymph node histology is indicated. The histological findings can provide certain clues about the etiology and also helps in the difficult differential diagnosis versus blastic non-Hodgkin lymphoma.

In cases of non-Hodgkin lymphoma and tumor metastases, a tentative diagnosis is possible on the basis of the lymph node cytology

a b

c

d

e

Fig. 65 Non-Hodgkin lymphoma and tumor metastases. a Lymph node cytology showing small cells with relatively wide cytoplasm (arrow 1) in addition to lymphocytes. There are scattered blasts with wide cytoplasm (arrow 2): lymphoplasmacytic immunocytoma. b Lymph node cytology showing exclusively large blastoid cells with a large central nucleolus (arrow). This usually indicates large-cell nonHodgkin lymphoma (in this case immunoblastic). c–e Metastatic disease from: c uterine carcinoma, d small-cell bronchial carcinoma, and e leiomyosarcoma.

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