Celeste N. Powers

Spindle-cell lesions of the mediastinum : Diagnosis by fine-needle aspiration biopsy

Spindle cells seen in fine‐needle aspiration biopsy (FNAB) of the mediastinal lesions can be a component of a wide variety of benign and malignant conditions. Few of these conditions, however, are described in the FNA cytopathology literature. This review discusses the cytopathologic features, differential diagnoses, and potential pitfalls of a variety of lesions with a significant component of spindle cells encountered in mediastinal FNAB. The cytopathology files from four institutions were searched for cases of mediastinal FNAB containing a spindle‐cell component that was a key or predominant cytologic feature of the diagnostic specimen. The cytomorphologic features of these cases were analyzed, and their differential features are discussed. Of 196 mediastinal FNABs, 22 (11%) were lesions with significant spindle‐cell component: granulomatous inflammation (four); benign nerve sheath tumor (four); thymic cyst (two); spindle‐cell thymoma (two); large‐cell non‐Hodgkins lymphoma with sclerosis (two); nodular sclerosing Hodgkins disease (two); liposarcoma (two); spindle‐cell squamous carcinoma possibly arising in a teratoma (one); unspecified high‐grade sarcoma (one); spindle‐cell malignant melanoma (one); and nonspecific fibrous tissue (one). The cytologic features of each lesion were analyzed as an aid for accurate classification. These findings were correlated with radiologic and clinical information when available. The value of ancillary studies performed on aspirated material in selected cases was also reviewed. FNA of mediastinal lesions with significant spindle‐cell morphology represents an infrequent and heterogeneous group of entities that may pose significant diagnostic challenges. This review presents the salient cytopathologic features of various spindle‐cell lesions of the mediastinum with particular emphasis on differential diagnosis and pitfalls. The pathologist must use caution when interpreting these lesions and ancillary studies may be of significant value in selected cases. Diagn. Cytopathol. 1997;17:167–176.

Thymoma mimicking lymphoblastic lymphoma: A pitfall in fine-needle aspiration biopsy interpretation

Lymphocyte‐rich thymoma often contains lymphoblasts, and lymphoblastic lymphoma often infiltrates the thymus gland. Although these two neoplasms are clinically distinct in most cases, their cytologic features may be similar on biopsy. We describe a fine‐needle aspiration biopsy of a thymoma in a 50‐yr‐old man to increase awareness of this pitfall in cytologic interpretation. Diagn Cytopathol 1996;14:165–171.

Adenoid basal carcinoma of the cervix: A potential pitfall in cervicovaginal cytology

Adenoid basal carcinoma (ABC) of the cervix is a quite uncommon, indolent, yet invasive neoplasm rarely identified on cervico‐vaginal smears. This may be due in part to sampling. Unless ABCs become ulcerated, even vigorous brushing of the endocervical canal may not be adequate to dislodge the small, cohesive cells of this neoplasm. Fortunately, the association of ABC with squamous intraepithelial lesions (SIL) often results in its incidental diagnosis on follow‐up cervical biopsy or endocervical curettage. We report two cases of ABC. In case 1, a 79‐yr‐old white woman was diagnosed with squamous‐cell carcinoma on cervicovaginal (CV) smear. High‐grade SIL, carcinoma in situ, and ABC were identified on subsequent cervical cone biopsy and hysterectomy. Retrospective evaluation of the CV smear revealed a few aggregates of small, uniform cells, with hyperchromatic nuclei representing fragments of ABC. In case 2, atypical basaloid cells suspicious for ABC were recognized on the CV smear of a 67‐yr‐old black woman, and ABC was subsequently confirmed on cervical cone biopsy. In neither case did the intervening cervical biopsy reveal ABC. In addition to a review of the clinical information useful in the diagnosis of ABC, the cytologic features of these two cases are compared with their subsequent histopathology and contrasted with other similar lesions comprising the differential diagnosis of small neoplastic cells found in cervicovaginal smears. Diagn Cytopathol 1996;14:172–177.