JAK2‐positive cutaneous myelofibrosis presenting as sclerosing extramedullary hematopoietic tumors on the scalp: case presentation and review of the literature

Abstract

We report the second case of cutaneous myelofibrosis with a documented JAK2 activating mutation involving the scalp of a 67-year-old woman with primary myelofibrosis in her marrow. In contrast to the previous case, the biopsy revealed extensive lesional collagen deposition and closely mimicked a fibrohistiocytic proliferation. Similar rare lesions occurring in the setting of myeloproliferative neoplasms have been called sclerosing extramedullary hematopoietic tumors. These entities appear histomorphologically and etiologically distinct from extramedullary hematopoiesis, and their diagnosis should prompt the workup for a myeloproliferative neoplasm in the absence of an antecedent diagnosis. The presence of the JAK2 mutation in our case confirmed that the lesions represented skin involvement by a neoplastic myeloid proliferation and not compensatory extramedullary hematopoiesis. Our patient died of disease several months following the appearance of her lesions, which is in keeping with other reports that suggest that cutaneous myelofibrosis may serve as an independent poor prognostic sign in otherwise advanced primary myelofibrosis. A review of the literature further emphasizes the importance of distinguishing this entity from mesenchymal neoplasms and acute myeloid leukemia involving the skin.

Alopecia neoplastica as a sign of visceral malignancies: a systematic review

“…Women were more represented with the 53.7% (66/123) of cases, compared to the 46.3% (57/123) of men . Median age of AN at onset was 59 (IQR: 47–68).…”

“…Regarding the primary site of malignancy, gastrointestinal (GI) tract accounted for 24.4% (30/123), breast for 17.9% (22/123) of cases, kidney for 8.1% (10/123), lung for 7.3% (9/123), thyroid for 7.3% (9/123), uterus for 6.5% (8/123), central nervous system (CNS) for 6.5% (8/123), liver for 3.3% (4/123) and other anatomic areas for 18.7% (23/123) of cases …”

“…Concerning histologic subtype of the primary tumour, carcinoma was the most reported with 53.7% (66/123) cases; of these, 38.2% (47/123) were adenocarcinomas, 7.3% (9/123) were squamous cell carcinomas and 0.8% (1/123) was a small cell carcinoma; while, in 7.3% (9/123) of cases, the type of carcinoma was not further specified . Regarding the remaining cases, 3.3% (4/123) primary tumours were leyomyosarcomas, 1.6% (2/123) were meningiomas, 40.7% (50/123) were other tumour subtypes and in one case of breast cancer, the histologic subtype was unknown (Table ) …”

“…Median time between primary tumour and AN diagnosis was 10 months (ranging from 0 to 240 months; IQR: 0-36). Finally, AN was the first metastatic event in 65 cases, 6,9,11,12,16,17,[19][20][21][22]24,28,34,36,37,39,41,51,54,56,60,62,67,70,72,[74][75][76][77]79,80,84,86,92,93,109,115,[117][118][119]121 with a median number of 1 lesion (ranging from 1 to 8) and a median diameter of 3 cm (ranging from 1 to 20 cm; IQR:1.5-4.7).…”

Sclerosing Extramedullary Hematopoietic Tumor

“…It is believed that sclerosis within the tumor was produced by fibroblasts, induced by cytokines released from clonal megakaryocytes. The presence of the JAK2 V617F mutation may also suggest the clonal nature of the lesion [ 4 ].…”