Clinicopathologic characteristics and outcomes of histiocytic and dendritic cell neoplasms: the moffitt cancer center experience over the last twenty five years

Abstract

Neoplasms of histiocytic and dendritic cells are rare disorders of the lymph node and soft tissues. Because of this rarity, the corresponding biology, prognosis and terminologies are still being better defined and hence historically, these disorders pose clinical and diagnostic challenges. These disorders include Langerhans cell histiocytosis (LCH), histiocytic sarcoma (HS), follicular dendritic cell sarcoma (FDCS), interdigtating cell sarcoma (IDCS), indeterminate cell sarcoma (INDCS), and fibroblastic reticular cell tumors (FRCT). In order to gain a better understanding of the biology, diagnosis, and treatment in these rare disorders we reviewed our cases of these neoplasms over the last twenty five years and the pertinent literature in each of these rare neoplasms. Cases of histiocytic and dendritic cell neoplasms diagnosed between 1989-2014 were identified using our institutional database. Thirty two cases were included in this analysis and were comprised of the following: Langerhans cell histiocytosis (20/32), histiocytic sarcoma (6/32), follicular dendritic cell sarcoma (2/32), interdigitating dendritic cell sarcoma (2/32), indeterminate dendritic cell sarcoma (1/32), and fibroblastic reticular cell tumor (1/32). Median overall survival was not reached in cases with LCH and showed 52 months in cases with HS, 12 months in cases with FDCS, 58 months in cases with IDCS, 13 months in the case of INDCS, and 51 months in the case of FRCT. The majority of patients had surgical resection as initial treatment (n = 18). Five patients had recurrent disease. We conclude that histiocytic and dendritic cell neoplasms are very rare and perplexing disorders that should be diagnosed with a combination of judicious morphology review and a battery of immunohistochemistry to rule out mimics such as carcinoma, lymphoma, neuroendocrine tumors and to better sub-classify these difficult to diagnose lesions. The mainstay of treatment for localized disease remains surgical resection and the role of adjuvant therapy is unclear. In patients with multiple areas of involvement, treatment at tertiary care centers with multimodality treatment is likely needed. Accurate subset diagnosis will contribute to better data as well as treatment outcomes analysis of these rare disorders of adult patients in the future.

Figure 1

Langerhans cell histiocytosis. (A) Histologically, there is admixture of histiocytes, Langerhans cells, few multinucleated cells, small lymphocytes and eosinophils (left panel, 200×) and low mitotic figures; (B) Cytologically, Langerhans cells nuclei have histiocytic features with pale fine chromatin pattern and accentuated dented, folded or pronounced nuclear grooves, pale to pinkish generous circumferential cytoplasm with some degree of cytologic atypia without anaplasia (right panel, 1000×).

Figure 2

Histiocytic sarcoma. Histologic pattern showed a diffuse infiltrate with focal sinusoidal pattern by large atypical neoplastic cells with pleomorphic nuclei and moderate to abundant cytoplasm.

Figure 3

Follicular dendritic cell sarcoma. Histologically, there is effaced architecture by a spindle cell proliferation. The spindle cells form fascicles and whorls (A). On closer magnification, the neoplastic cells show admixed spindled to ovoid nuclei with indistinct cytoplasmic borders, mitosis and mild pleomorphism. Rare small lymphocytes are seen in the background.

Figure 4

Interdigitating dendritic cell sarcoma. (A) Sinusoidal pattern by large neoplastic cells with elongated nuclei, copious pink cytoplasm, and indistinct cell borders with rare mitosis; (B) On high magnification, the spindle cells show mild to moderate nuclear atypia, hyperchromatism and mild pleomorphism with sheets of small lymphocytes.

Figure 5

Indeterminate dendritic cell sarcoma: (A) Low power view showing deep diffuse dermal tumor nodule extending to subcutis; (B) High power shows the histiocytic infiltrate with spindly to dendritic to polygonal cells with oval to pleomorphic nuclei, abundant pink cytoplasm adjacent to a hypertrophic arteriole.